ECIA Encision Inc (PK)

Management

Investment Adviser.  Boston Management and Research (“BMR”).

Portfolio Manager.  The Portfolio is managed by Susan Schiff, Vice President of BMR, who has managed the Portfolio since its inception in 1992.

For important information about purchase and sale of shares, taxes and financial intermediary compensation, please turn to “Important Information Regarding Fund Shares” on page 21 of this Prospectus.

Eaton Vance Fixed Income Funds

6

Prospectus dated March 1, 2014

Eaton Vance High Income Opportunities Fund

Investment Objectives

The Fund’s primary investment objective is to provide a high level of current income. The Fund seeks growth of capital as a secondary investment objective.

Management

Investment Adviser.  Boston Management and Research (“BMR”).

Portfolio Manager.   The Portfolio is managed by Michael Weilheimer, Vice President of BMR, who has either managed or co-managed the Portfolio since 1996.

For important information about purchase and sale of shares, taxes and financial intermediary compensation, please turn to “Important Information Regarding Fund Shares” on page 21 of this Prospectus.

Eaton Vance Fixed Income Funds

11

Prospectus dated March 1, 2014

Eaton Vance Income Fund of Boston

Investment Objectives

The Fund’s investment objective is to provide a high level of current income. The Fund's secondary objectives are to seek growth of income and capital.

Management

Investment Adviser.  Boston Management and Research (“BMR”).

Portfolio Manager.   The Portfolio is managed by Michael Weilheimer, Vice President of BMR, who has either managed or co-managed the Portfolio since its inception in 2001.

For important information about purchase and sale of shares, taxes and financial intermediary compensation, please turn to “Important Information Regarding Fund Shares” on page 21 of this Prospectus.

Eaton Vance Fixed Income Funds

16

Prospectus dated March 1, 2014

Eaton Vance Short Duration Government Income Fund

Investment Objective

The Fund’s investment objective is to seek total return.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.  You may qualify for a reduced sales charge if you invest, or agree to invest over a 13-month period, at least $100,000 in Eaton Vance funds.  More information about these and other discounts is available from your financial intermediary and in Sales Charges beginning on page 35 of this Prospectus and page 22 of the Fund’s Statement of Additional Information.  

 ⁽¹⁾

Reflects the Fund’s allocable share of the advisory fees and other expenses of the Portfolios in which it invests.

Example.  This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.  The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods.  The Example also assumes that your investment has a 5% return each year and that the operating expenses remain the same.  Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Portfolio Turnover

The Fund and the Portfolios in which it invests (see below) pay transaction costs, such as commissions, when they buy and sell securities (or “turns over” the portfolio).  A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account.  These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 35 % of the average value of its portfolio.

Management

Investment Adviser.  Eaton Vance Management (“Eaton Vance”).

Portfolio Manager.  The Fund is managed by Susan Schiff, Vice President of Eaton Vance, who has managed the Fund since its inception in 2002.

Important Information Regarding Fund Shares

Purchase and Sale of Fund Shares

You may purchase, redeem or exchange Fund shares on any business day, which is any day the New York Stock Exchange is open for business.  Class B shares are only available for purchase upon exchange from another Eaton Vance fund or through reinvestment of distributions. You may purchase, redeem or exchange Fund shares either through your financial intermediary or directly from the Fund either by writing to the Fund, P.O. Box 9653, Providence, RI 02940-9653, or by calling 1-800-262-1122.  The minimum initial purchase or exchange into a Fund is $1,000 for each Class (with the exception of Class I) and $250,000 for Class I (waived in certain circumstances).  There is no minimum for subsequent investments.

Tax Information

Each Fund’s distributions are expected to be taxed as ordinary income and/or capital gains, unless you are exempt from taxation.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase Fund shares through a broker-dealer or other financial intermediary (such as a bank) (collectively, “financial intermediaries”), a Fund, its principal underwriter and its affiliates may pay the financial intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the financial intermediary and your salesperson to recommend a Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

Eaton Vance Fixed Income Funds

21

Prospectus dated March 1, 2014

Investment Objectives & Principal Policies and Risks

Each Fund and Portfolio are permitted to engage in the following investment practices to the extent set forth in “Fund Summaries” above or, in the case of the Portfolios, in “Further Information about the Portfolios .” References to the “Fund” below are to each Fund and Portfolio, as applicable.

A statement of the investment objective(s) and principal investment policies and risks of the Fund is set forth above in Fund Summaries. As noted in each Fund Summary, each Fund seeks to achieve its investment objective(s) by investing in the Portfolio or Portfolios named therein.   Set forth below is additional information about such policies and risks of the Fund described in Fund Summaries above. Information also is included about other types of investments and practices that the Fund may engage in from time to time.

As noted in its Fund Summary, Short Duration Government Income Fund seeks to achieve its investment objective primarily by allocating its assets among other registered investment companies managed by Eaton Vance and its affiliates that invest in various asset classes (collectively, the “Portfolios”).  Such Portfolios are listed below:

•

CMBS Portfolio;

•

Floating Rate Portfolio;

•

Government Obligations Portfolio;

•

Senior Debt Portfolio;

•

Short Duration High Income Portfolio; and

•

Short-Term U.S. Government Portfolio

Fixed-income Securities.   Fixed-income securities include all types of fixed and floating-rate bonds and notes, such as convertible securities; corporate commercial paper; mortgage-backed and other asset-backed securities; inflation-indexed bonds issued by both governments and corporations; structured notes, including hybrid or “indexed” securities; loans; loan participations and assignments; delayed funding loans and revolving credit facilities; preferred securities; and bank certificates of deposit, fixed time deposits, bank deposits (or investments structured to provide the same type of exposure) and bankers’ acceptances of foreign and domestic banks and other debt instruments. Fixed-income securities are issued by: foreign governments or their subdivisions, agencies and government-sponsored enterprises; international agencies or supranational entities; the U.S. Government, its agencies or government-sponsored enterprises (or guaranteed thereby); central or quasi-sovereign banks and U.S. and foreign corporations.  Fixed-income securities include deep discount bonds, such as zero coupon bonds, deferred interest bonds, bonds or securities on which the interest is payable in-kind (“PIK securities”), which are debt obligations that are issued at a significant discount from face value, and securities purchased on a forward commitment or when-issued basis. While zero coupon bonds do not make periodic payments of interest, deferred interest bonds provide for a period of delay before the regular payment of interest begins. PIK securities provide that the issuer thereof may, at its option, pay interest in cash or in the form of additional securities.

Mortgage-Backed Securities (“MBS”).  MBS represent participation interests in pools of adjustable and fixed-rate mortgage loans. MBS may be issued by the U.S. Government (or one of its agencies or instrumentalities) or privately issued but collateralized by mortgages that are insured, guaranteed or otherwise backed by the U.S. Government, or its agencies or instrumentalities. Adjustable rate mortgages are mortgages whose interest rates are periodically reset when market rates change. Unlike conventional debt obligations, MBS provide monthly payments derived from the monthly interest and principal payments (including any prepayments) made by the individual borrowers on the pooled mortgage loans. MBS that include loans that have had a history of refinancing opportunities are referred to as “seasoned MBS .” MBS that are not seasoned MBS are referred to as generic MBS. Seasoned MBS tend to have a higher collateral to debt ratio than other MBS because a greater percentage of the underlying debt has been repaid and the collateral property may have appreciated in value. MBS may be “premium bonds” acquired at prices that exceed their par or principal value.

The mortgage loans underlying MBS are generally subject to a greater rate of principal prepayments in a declining interest rate environment and to a lesser rate of principal prepayments in an increasing interest rate environment, although investment in seasoned MBS can mitigate this risk. Under certain interest and prepayment rate scenarios, the Fund may fail to recover the full amount of its investment in MBS, notwithstanding any direct or indirect governmental or agency guarantee.  Moreover, if the Fund invests in interest only stripped MBS , it may fail to recoup its initial investment if the underlying mortgages experience greater than anticipated prepayments of principal.  Because faster than expected prepayments must usually be invested in lower yielding securities, MBS are less effective than conventional bonds in “locking in” a specified interest rate. For premium bonds, prepayment risk may be enhanced. In a rising interest rate environment, a declining prepayment rate will extend the average life of many MBS. This possibility is often referred to as extension risk. Extending the average life of a mortgage-backed security increases the risk of depreciation due to future increases in market interest rates. MBS that are purchased at a premium generate current income that exceeds market rates for comparable investments, but tend to decrease in value as they mature. MBS

Eaton Vance Fixed Income Funds

22

Prospectus dated March 1, 2014

include classes of collateralized mortgage obligations (“CMOs”), including fixed- or floating-rate tranches, and various other MBS. In choosing among CMO classes, the investment adviser will evaluate the total income potential of each class and other factors. CMOs are subject to the same types of risks affecting MBS as described above. Mortgage dollar rolls involve the Fund selling MBS for delivery in the current month with a simultaneous contract entered to repurchase substantially similar (same type, coupon and maturity) securities on a specified future date (a “mortgage roll”). During the roll period, the Fund foregoes principal and interest paid on the MBS.

Lower Rated Bonds.  Although the investment adviser considers security ratings when making investment decisions, it performs its own credit and investment analysis and does not rely primarily on the ratings assigned by the rating agencies.  In evaluating the quality of a particular security, whether rated or unrated, the investment adviser will normally take into consideration, among other things, the issuer’s financial resources and operating history, its sensitivity to economic conditions and trends, the ability of its management, its debt maturity schedules and borrowing requirements, and relative values based on anticipated cash flow, interest and asset coverage, and earnings prospects.  Credit ratings are based largely on the issuer’s historical financial condition and a rating agency’s investment analysis at the time of rating: the rating assigned to any particular security is not necessarily a reflection of the issuer’s current financial condition.  The rating assigned to a security by a rating agency does not reflect assessment of the volatility of the security’s market value or of the liquidity of an investment in the security.  Credit quality in the sectors of the market can change from time to time, and recently issued credit ratings may not fully reflect the actual risks posed by a particular security.

Because of the greater number of investment considerations involved in investing in high yield, high risk bonds, the achievement of the Fund’s objective(s) depends more on the investment adviser’s judgment and analytical abilities than would be the case if the Fund invested primarily in securities in the higher rating categories.  While the investment adviser will attempt to reduce the risks of investing in lower rated or unrated securities through active portfolio management, diversification, credit analysis and attention to current developments and trends in the economy and the financial markets, there can be no assurance that a broadly diversified portfolio of such securities would substantially lessen the risks of defaults brought about by an economic downturn or recession.  Moreover, the Fund may invest up to 25% of its assets in any one industry, which may expose the Fund to unique risks of that industry.  The Fund’s investments may have significant exposure to certain sectors of the economy and thus may react differently to political or economic developments than the market as a whole.

Foreign and Emerging Market Investments.  Investments in foreign issuers could be affected by factors not present in the United States, including expropriation, armed conflict, confiscatory taxation, lack of uniform accounting and auditing standards, less publicly available financial and other information, and potential difficulties in enforcing contractual obligations. Because foreign issuers may not be subject to uniform accounting, auditing and financial reporting standard practices and requirements and regulatory measures comparable to those in the United States, there may be less publicly available information about such foreign issuers.  Settlements of securities transactions in foreign countries are subject to risk of loss, may be delayed and are generally less frequent than in the United States, which could affect the liquidity of the Fund’s assets.

The Fund may invest in securities and other instruments (including loans) issued , guaranteed , or backed by sovereign entities.  Economic data as reported by foreign governments and other issuers may be delayed, inaccurate or fraudulent. In the event of a default by a sovereign entity, there are typically no assets to be seized or cash flows to be attached. Furthermore, the willingness or ability of a foreign government to renegotiate defaulted debt may be limited. Therefore, losses on sovereign defaults may far exceed the losses from the default of a similarly rated U.S. corporate debt issuer.

The foregoing risks of foreign investing can be more significant in less developed countries characterized as emerging market countries, which may offer higher potential for gains and losses than investments in the developed markets of the world. Political and economic structures in emerging market countries generally lack the social, political and economic stability of developed countries, which may affect the value of the Fund’s investments in these countries and also the ability of the Fund to access markets in such countries. Governmental actions can have a significant effect on the economic conditions in emerging market countries, which also may adversely affect the value and liquidity of the Fund’s investments. The laws of emerging market countries relating to the limited liability of corporate shareholders, fiduciary duties of officers and directors, and bankruptcy of state enterprises are generally less well developed than or different from such laws in the United States. It may be more difficult to obtain a judgment in the courts of these countries than it is in the United States. Disruptions due to work stoppages and trading improprieties in foreign securities markets have caused such markets to close. If extended closings were to occur in stock markets where the Fund is heavily invested, the Fund’s ability to redeem Fund shares could become impaired. In such circumstances, the Fund may have to sell more liquid securities than it would otherwise choose to sell.  Emerging market securities are also subject to speculative trading, which contributes to their volatility.

Foreign Currencies.  The value of foreign assets and currencies as measured in U.S. dollars may be affected favorably or unfavorably by changes in foreign currency rates and exchange control regulations, application of foreign tax laws (including withholding tax), governmental administration of economic or monetary policies (in this country or abroad), and relations

Eaton Vance Fixed Income Funds

23

Prospectus dated March 1, 2014

between nations and trading.  Foreign currencies also are subject to settlement, custodial and other operational risks. Currency exchange rates can be affected unpredictably by intervention by U.S. or foreign governments or central banks, or the failure to intervene, or by currency controls or political developments in the United States or abroad.  Costs are incurred in connection with conversions between currencies.  The Fund may engage in spot transactions and forward foreign currency exchange contracts, purchase and sell options on currencies and purchase and sell currency futures contracts and related options thereon (collectively, “Currency Instruments”) to seek to hedge against the decline in the value of currencies in which its portfolio holdings are denominated against the U.S. dollar or to seek to enhance returns.  Use of Currency Instruments may involve substantial currency risk and may also involve counterparty, leverage or liquidity risk.

Derivatives.  The Fund may enter into derivatives transactions with respect to any security or other instrument in which it is permitted to invest or any related security, instrument, index or economic indicator (“reference instruments”). The Fund may engage in derivative transactions to seek return, to hedge against fluctuations in securities prices, interest rates or currency exchange rates, or as a substitute for the purchase or sale of securities or currencies.  Derivatives are financial instruments the value of which is derived from the underlying reference instrument. Derivatives transactions can involve substantial risk.  Derivatives typically allow the Fund to increase or decrease the level of risk to which the Fund is exposed more quickly and efficiently than transactions in other types of instruments.  The Fund incurs costs in connection with opening and closing derivatives positions.  The Fund may engage in the derivative transactions set forth below, as well as in other derivative transactions with substantially similar characteristics and risks.

Certain derivative transactions may give rise to a form of leverage.  The Fund is required to segregate or “earmark” liquid assets or otherwise cover the Fund’s obligation created by a transaction that may give rise to leverage.  The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements.  Leverage may cause the Fund’s share price to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the value of the Fund’s portfolio securities.  The loss on leverage transactions may substantially exceed the initial investment.

The use of derivatives can lead to losses because of adverse movements in the price or value of the asset, index, rate or instrument underlying a derivative, due to failure of a counterparty or due to tax or regulatory constraints. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund.  When derivatives are used to gain or limit exposure to a particular market or market segment, their performance may not correlate as expected to the performance of such market thereby causing the Fund to fail to achieve its original purpose for using such derivatives. A decision as to whether, when and how to use derivatives involves the exercise of specialized skill and judgment, and even a well-conceived transaction may be unsuccessful to some degree because of market behavior or unexpected events.  Derivative instruments may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying instrument.  If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in the return of collateral or other assets held by the counterparty.  The loss on derivative transactions may substantially exceed the initial investment.

Options on Securities, Indices and Currencies.  The Fund may engage in transactions in exchange-traded and over-the-counter (“OTC”) options.  There are several risks associated with transactions in options such as imperfect correlation, counterparty risk and an insufficient liquid secondary market for particular options.  By buying a put option, the Fund acquires a right to sell the underlying instrument at the exercise price, thus limiting the Fund's risk of loss through a decline in the market value of the instrument until the put option expires. The Fund will pay a premium to the seller of the option for the right to receive payments of cash to the extent that the value of the applicable instrument declines below the exercise price as of the option valuation date.  If the price of the instrument is above the exercise price of the option as of the option valuation date, the option expires worthless and the Fund will not be able to recover the option premium paid to the seller.  The Fund may purchase uncovered put options.  The Fund also has authority to write (i.e., sell) put options. The Fund will receive a premium for writing a put option, which increases the Fund's return. In writing a put option, the Fund has the obligation to buy the underlying instrument at an agreed upon price if the price of such instrument decreases below the exercise price.  If the value of the instrument on the option expiration date is above the exercise price, the option will generally expire worthless and the Fund, as option seller, will have no obligation to the option holder.

A purchased call option gives the Fund the right to buy, and obligates the seller to sell, the underlying instrument at the exercise price at any time during the option period.  The Fund also is authorized to write (i.e., sell) call options on instruments in which it may invest and to enter into closing purchase transactions with respect to such options.  A covered call option is an option in which the Fund, in return for a premium, gives another party a right to buy specified instruments owned by the Fund at a specified future date and price set at the time of the contract. The Fund's ability to sell the instrument underlying a call option may be limited while the option is in effect unless the Fund enters into a closing purchase transaction. Uncovered call options have speculative characteristics and are riskier than covered call options

Eaton Vance Fixed Income Funds

24

Prospectus dated March 1, 2014

because there is no underlying instrument held by the Fund that can act as a partial hedge.  As the writer of a covered call option or an index call option, the Fund forgoes, during the option’s life, the opportunity to profit from increases in the market value of the security or the index covering the call option above the sum of the option premium received and the exercise price of the call, but has retained the risk of loss, minus the option premium received, should the price of the underlying security or index decline.

OTC options involve risk that the issuer or counterparty will fail to perform its contractual obligations. Participants in these markets are typically not subject to the same credit evaluation and regulatory oversight as are members of “exchange-based” markets. By engaging in option transactions in these markets, the Fund may take a credit risk with regard to parties with which it trades and also may bear the risk of settlement default.

The Fund may also enter into swaptions, which are options giving the option owner the right (but not the obligation) to enter into or cancel a swap agreement at a future date.

Futures Contracts.  The Fund may engage in transactions in futures contracts and options on futures contracts. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price.  The Fund also is authorized to purchase or sell call and put options on futures contracts.  The primary risks associated with the use of futures contracts and options are imperfect correlation, liquidity, unanticipated market movement and counterparty risk.

Forward Foreign Currency Exchange Contracts.   Certain forward foreign currency exchange contracts may be individually negotiated and privately traded so they are dependent upon the creditworthiness of the counterparty. Forward contracts are subject to the risk of political and economic factors applicable to the countries issuing the underlying currencies. Furthermore, unlike trading in most other types of instruments, there is no systematic reporting of last sale information with respect to the foreign currencies underlying forwards. As a result, available information may not be complete.

Interest Rate Swaps.  Interest rate swaps involve the exchange by the Fund with another party of their respective commitments to pay or receive interest, e.g., an exchange of fixed rate payments for floating rate payments  Interest rate swaps involve counterparty risk and the risk of imperfect correlation.

Credit Default Swaps.  Credit default swap agreements (“CDS”) enable the Fund to buy or sell credit protection on an individual issuer or basket of issuers (i.e., the reference instrument).  The Fund may enter into CDS to gain or short exposure to a reference instrument. Long CDS positions are utilized to gain exposure to a reference instrument (similar to buying the instrument) and are akin to selling insurance on the instrument. Short CDS positions are utilized to short exposure to a reference instrument (similar to shorting the instrument) and are akin to buying insurance on the instrument. In response to market events, federal and certain state regulators have proposed regulation of the CDS market. These regulations may limit the Fund’s ability to use CDS and/or the benefits of CDS. CDS involve risks, including the risk that the counterparty may be unable to fulfill the transaction or that the Fund may be required to purchase securities or other instruments to meet delivery obligations.  The Fund may have difficulty, be unable or may incur additional costs to acquire such securities or instruments.

Inflation Swaps.  Inflation swaps involve the exchange by the Fund with another party of their respective commitments to pay or receive interest, e.g. , an exchange of fixed rate payments for floating rate payments or an exchange of floating rate payments based on two different reference indices. By design, one of the reference indices is an inflation index, such as the Consumer Price Index. Inflation swaps can be designated as zero coupon, where both sides of the swap compound interest over the life of the swap and then the accrued interest is paid out only at the swap’s maturity.

Credit Linked Notes, Credit Options and Similar Investments.  Credit linked notes are obligations between two or more parties where the payment of principal and/or interest is based on the performance of some obligation, basket of obligations, index or economic indicator (a “reference instrument”). In addition to the credit risk associated with the reference instrument and interest rate risk, the buyer and seller of a credit linked note or similar structured investment are subject to counterparty risk. Credit options are options whereby the purchaser has the right, but not the obligation, to enter into a transaction involving either an asset with inherent credit risk or a credit derivative, at terms specified at the initiation of the option. These transactions involve risks, including counterparty risk.

Forward Rate Agreements.  Under forward rate agreements, the buyer locks in an interest rate at a future settlement date. If the interest rate on the settlement date exceeds the lock rate, the buyer pays the seller the difference between the two rates. If the lock rate exceeds the interest rate on the settlement date, the seller pays the buyer the difference between the two rates.  These transactions involve risks, including counterparty risk.

Total Return Swaps.  In a total return swap, the buyer receives a periodic return equal to the total return of a specified security, securities or index, for a specified period of time. In return, the buyer pays the counterparty a variable stream of payments, typically based upon short term interest rates, possibly plus or minus an agreed upon spread.  These transactions involve risks, including counterparty risk.

Eaton Vance Fixed Income Funds

25

Prospectus dated March 1, 2014

Short Sales.  The Fund may engage in covered short sales (on individual securities held or on an index or basket of securities whose constituents are held in whole or in part or for which liquid assets have been segregated).  A short sale on an individual security typically involves the sale of a security that is borrowed from a broker or other institution to complete the sale. Short sales expose the seller to the risk that it will be required to acquire securities to replace the borrowed securities (also known as “covering” the short position) at a time when the securities sold short have appreciated in value, thus resulting in a loss. When making a short sale, the Fund must segregate liquid assets equal to (or otherwise cover) its obligations under the short sale.  The seller of a short position generally realizes a profit on the transaction if the price it receives on the short sale exceeds the cost of closing out the position by purchasing securities in the market, but generally realizes a loss if the cost of closing out the short position exceeds the proceeds of the short sale.

Floating Rate Loans.  Senior floating-rate loans (“Senior Loans”) hold a senior position in the capital structure of a business entity (the “Borrower”), are typically secured with specific collateral and have a claim on the assets and/or stock of the Borrower that is senior to that held by subordinated debtholders and stockholders of the Borrower. Senior Loans typically have rates of interest which are re-determined daily, monthly, quarterly or semi-annually by reference to a base lending rate, plus a premium. Senior Loans held by the Fund typically have a dollar-weighted average period until the next interest rate adjustment of approximately 90 days or less. Junior loans are secured and unsecured subordinated loans, second lien loans and subordinated bridge loans (“Junior Loans”). Junior Loans are subject to the same general risks inherent to any loan investment. Due to their lower place in the Borrower’s capital structure and possible unsecured status, Junior Loans involve a higher degree of overall risk than Senior Loans of the same Borrower.

Most loans are lower rated investments. In the event a loan is not rated, it is likely to be the equivalent in quality to a lower rated investment. The amount of public information available with respect to loans may be less extensive than that available for registered or exchange listed securities. In evaluating the creditworthiness of Borrowers, the investment adviser will consider, and may rely in part, on analyses performed by others.

Duration.  Duration measures the time-weighted expected cash flows of a fixed-income security, which can determine its sensitivity to changes in the general level of interest rates.  Securities with longer durations tend to be more sensitive to interest rate changes than securities with shorter durations.  A mutual fund with a longer dollar-weighted average duration can be expected to be more sensitive to interest rate changes than a fund with a shorter dollar-weighted average duration.  Duration differs from maturity in that it considers a security’s coupon payments in addition to the amount of time until the security matures.  Various techniques may be used to shorten or lengthen Fund duration.  As the value of a security changes over time, so will its duration.

Credit Quality.  Rating agencies are private services that provide ratings of the credit quality of certain loans and other income securities.  In evaluating creditworthiness, the investment adviser considers ratings assigned by rating agencies and generally performs additional credit and investment analysis.  Credit ratings issued by rating agencies are based on a number of factors including, but not limited to, the issuer’s financial condition and the rating agency’s credit analysis, if applicable, at the time of rating.  The ratings assigned are not absolute standards of credit quality and do not evaluate market risks or necessarily reflect the issuer’s current financial condition. An issuer’s current financial condition may be better or worse than the current rating indicates. A credit rating may have a modifier (such as plus, minus or a numerical modifier) to denote its relative status within the rating. The presence of a modifier does not change the security credit rating (for example, BBB- and Baa3 are within the investment grade rating) for purposes of the Fund’s investment limitations.  If a security is rated differently by rating agencies, the modifier rating will be used for any Fund rating restrictions.

Asset-Backed Securities.  Asset-backed securities represent interests in a pool of assets, such as home equity loans, commercial mortgage-backed securities (“CMBS”), automobile receivables or credit card receivables.  Unscheduled prepayments of asset-backed securities may result in a loss of income if the proceeds are invested in lower-yielding securities.  In addition, issuers of asset-backed securities may have limited ability to enforce the security interest in the underlying assets, and credit enhancements (if any) may be inadequate in the event of default.   Asset-backed securities may experience losses on the underlying assets as a result of certain rights provided to consumer debtors under federal and state law.  The value of asset-backed securities may be affected by the factors described above and other factors, such as the availability of information concerning the pool and its structure, the creditworthiness of the servicing agent for the pool, the originator of the underlying assets or the entities providing credit enhancements and the ability of the servicer to service the underlying collateral.  The value of asset-backed securities representing interests in a pool of utilities receivables may be adversely affected by changes in government regulations.  Under certain market conditions, asset-backed securities may be less liquid and may be difficult to value.

Commercial Mortgage-Backed Securities.   CMBS include securities that reflect an interest in, and are secured by, mortgage loans on commercial real property. CMBS are subject to the risks described under “Asset-Backed Securities” above. CMBS also are subject to many of the risks of investing in the real estate securing the underlying mortgage loans. These risks reflect the effects of local and other economic conditions on real estate markets, the ability of tenants to make loan payments, and the

Eaton Vance Fixed Income Funds

26

Prospectus dated March 1, 2014

ability of a property to attract and retain tenants. CMBS may be less liquid and exhibit a greater price volatility than other types of mortgage- or asset-backed securities. The Fund's direct and indirect investments in CMBS will not exceed 25% of its net assets. For the purposes of the Fund's industry concentration policy, CMBS will be categorized based on the underlying assets of the CMBS (retail, office, warehouse, multifamily, defeased collateral, etc.).

The commercial mortgage loans that underlie CMBS have certain distinct risk characteristics. Commercial mortgage loans generally lack standardized terms, which may complicate their structure, tend to have shorter maturities than residential mortgage loans and may not be fully amortizing. Commercial properties themselves tend to be unique and are more difficult to value than single-family residential properties. In addition, commercial properties, particularly industrial and warehouse properties, are subject to environmental risks and the burdens and costs of compliance with environmental laws and regulations.

Inflation-Indexed Bonds.  Inflation-indexed bonds (other than municipal inflation-indexed bonds and certain corporate inflation-indexed bonds ) are fixed-income securities whose principal value is periodically adjusted according to the rate of inflation. If the index measuring inflation falls, the principal value of inflation-indexed bonds (other than municipal inflation-indexed bonds and certain corporate inflation-indexed bonds) will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed by the U.S. Treasury in the case of U.S. Treasury inflation-indexed bonds. For bonds that do not provide a similar guarantee, the adjusted principal value of the bond repaid at maturity may be less than the original principal.

Event-Linked Instruments.  The Fund may obtain event-linked exposure by investing in “event-linked bonds” or “event-linked swaps” or by implementing “event-linked strategies.” Event-linked exposure results in gains or losses that typically are contingent, or formulaically related to defined trigger events. Examples of trigger events include hurricanes, earthquakes, weather-related phenomena, or statistics relating to such events. Some event-linked bonds are commonly referred to as “catastrophe bonds.” If a trigger event occurs, the Fund may lose a portion of its entire principal invested in the bond or notional amount on a swap. Event-linked exposure often provides for an extension of maturity to process and audit loss claims where a trigger event has, or possibly has, occurred. An extension of maturity may increase volatility. Event-linked exposure may also expose the Fund to certain unanticipated risks, including credit risk, counterparty risk, adverse regulatory or jurisdictional interpretations, and adverse tax consequences. Event-linked exposures may also be subject to liquidity risk.

U.S. Government Securities.  U.S. Government securities include U.S. Treasury obligations, which differ in their interest rates, maturities and times of issuance, and obligations issued or guaranteed by U.S. Government agencies or instrumentalities (“agency obligations”). Agency obligations may be guaranteed by the U.S. Government or they may be backed by the right of the issuer to borrow from the U.S. Treasury, the discretionary authority of the U.S. Government to purchase the obligations, or the credit of the agency or instrumentality. U.S. Government securities also include any other security or agreement collateralized or otherwise secured by U.S. Government securities.  As a result of their high credit quality and market liquidity, U.S. Government securities generally provide a lower current return than obligations of other issuers.

Equity Investments.  Equity investments include U.S. and non-U.S. common stocks, interests in baskets or indices of equity securities, income or non-income producing equity securities or warrants and equity securities received upon conversion of convertible securities, such as convertible bonds.

Convertible Securities.  A convertible security is a bond, debenture, note, preferred security, or other security that entitles the holder to acquire common stock or other equity securities of the same or a different issuer.   A convertible security entitles the holder to receive interest paid or accrued on debt or the dividend paid on preferred securities until the convertible security matures or is redeemed, converted or exchanged. Before conversion, convertible securities have characteristics similar to nonconvertible income securities. The value of a convertible security is influenced by changes in interest rates, with investment value declining as interest rates increase and increasing as interest rates decline. The credit standing of the issuer and other issuer and market factors also may have an effect on the convertible security’s value. A convertible security may be subject to redemption at the option of the issuer at a price established in the convertible security’s governing instrument.

Municipal Obligations.  Municipal obligations include bonds, notes, floating-rate notes and commercial paper issued by municipalities and agencies and authorities established by those municipalities. Municipal debt may be used for a wide variety of public and private purposes, and the interest thereon may or may not be subject to U.S. federal income tax.  Municipal obligations also include municipal leases and participations in municipal leases.   An issuer’s obligation under such leases is often subject to the appropriation by a legislative body, on an annual or other basis, of funds for the payment of the obligations.   Certain municipal obligations may be purchased on a “when-issued” basis, which means that payment and delivery occur on a future settlement date. The price and yield of such securities are generally fixed on the date of commitment to purchase.

Eaton Vance Fixed Income Funds

27

Prospectus dated March 1, 2014

Repurchase Agreements.  A repurchase agreement is the purchase by the Fund of securities from a counterparty in exchange for cash that is coupled with an agreement to resell those securities to the counterparty at a specified date and price. Repurchase agreements that mature in more than seven days will be treated as illiquid. When a repurchase agreement is entered into, the Fund typically receives securities with a value that equals or exceeds the repurchase price, including any accrued interest earned on the agreement. The value of such securities will be marked to market daily, and cash or additional securities will be exchanged between the parties as needed. Except in the case of a repurchase agreement entered into to settle a short sale, the value of the securities delivered to the Fund will be at least equal to 90% of such repurchase price during the term of the repurchase agreement. The terms of a repurchase agreement entered into to settle a short sale may provide that the cash purchase price paid by the Fund is more than the value of purchased securities that effectively collateralize the repurchase price payable by the counterparty. Since in such a transaction the Fund normally will have used the purchased securities to settle the short sale, the Fund will segregate liquid assets equal to the marked to market value of the purchased securities that it is obligated to return to the counterparty under the repurchase agreement.

Reverse Repurchase Agreements.  The Fund may enter into reverse repurchase agreements. Under a reverse repurchase agreement, the Fund transfers possession of a portfolio instrument to another party, such as a bank or broker-dealer, in return for cash. At the same time, the Fund agrees to repurchase the instrument at an agreed upon time (normally within seven days) and price, which reflects an interest payment.  The Fund may enter into such agreements when it believes it is able to invest the cash acquired at a rate higher than the cost of the agreement, which would increase earned income.  The Fund could also enter into reverse repurchase agreements as a means of raising cash to satisfy redemption requests without the necessity of selling portfolio assets.

Cash and Cash Equivalents.  The Fund may invest in cash or cash equivalents, including high quality short-term instruments or an affiliated investment company that invests in such instruments.

Forward Commitments.  Fixed-income securities may be purchased on a “forward commitment” or “when-issued” basis (meaning securities are purchased or sold with payment and delivery taking place in the future). In such a transaction, the Fund is securing what is considered to be an advantageous price and yield at the time of entering into the transaction. However, the yield on a comparable security when the transaction is consummated may vary from the yield on the security at the time that the forward commitment or when-issued transaction was made. From the time of entering into the transaction until delivery and payment is made at a later date, the securities that are the subject of the transaction are subject to market fluctuations. In forward commitment or when-issued transactions, if the seller or buyer, as the case may be, fails to consummate the transaction, the counterparty may miss the opportunity of obtaining a price or yield considered to be advantageous. Forward commitment or when-issued transactions may be expected to occur a month or more before delivery is due. However, no payment or delivery is made until payment is received or delivery is made from the other party to the transaction.

Securities Lending.  The Fund may lend its portfolio securities to broker-dealers and other institutional borrowers.  During the existence of a loan, the Fund will continue to receive the equivalent of the interest paid by the issuer on the securities loaned, or all or a portion of the interest on investment of the collateral, if any. The Fund may pay lending fees to such borrowers. As with other extensions of credit, there are risks of delay in recovery or even loss of rights in the securities loaned if the borrower of the securities fails financially. Loans only will be made to firms that have been approved by the investment adviser and the investment adviser or the securities lending agent will periodically monitor the financial condition of such firms while such loans are outstanding. Securities loans only will be made when the investment adviser believes that the expected returns, net of expenses, justifies the attendant risks. The Fund may engage in securities lending for total return as well as for income, and expects to invest the collateral received from loans in securities in which the Fund may invest. To the extent that the portfolio securities acquired with such collateral have decreased in value, it may result in the Fund realizing a loss at a time when it would not otherwise do so. This risk is substantially the same as that incurred through investment leverage. The Fund also may incur losses if the returns on securities that it acquires with cash collateral are less than the applicable rebate rates paid to borrowers and related administrative costs. Upon return of the loaned securities, the Fund would be required to return the related collateral to the borrower and may be required to liquidate portfolio securities in order to do so.  The Fund may lend up to one-third of the value of its total assets or such other amount as may be permitted by law.

Pooled Investment Vehicles.  Subject to applicable limitations, the Fund may invest in pooled investment vehicles, including open- and closed-end investment companies affiliated or unaffiliated with the investment adviser, and exchange-traded funds. The market for common shares of closed-end investment companies and exchange-traded funds, which are generally traded on an exchange, is affected by the demand for those securities, regardless of the value of the fund’s underlying portfolio assets.  The Fund will indirectly bear its proportionate share of any management fees and expenses paid by unaffiliated and certain affiliated pooled investment vehicles in which it invests, except that management fees of affiliated funds may be waived.     If they exceed 0.01%, the costs associated with such investments will be reflected in Acquired Fund Fees and Expenses in the Annual Fund Operating Expenses in Fund Summaries.

Eaton Vance Fixed Income Funds

28

Prospectus dated March 1, 2014

Borrowing. Government Obligations Fund and Short Duration Government Income Fund are authorized to borrow in accordance with applicable regulations to increase assets. The Fund will borrow for the purpose of acquiring additional investments when it believes that the interest payments and other costs with respect to such borrowings will be exceeded by the anticipated total return (a combination of income and appreciation) on such investments.  Successful use of a borrowing strategy depends on the investment adviser’s ability to predict correctly interest rates and market movements. The Fund is required to maintain continuous asset coverage with respect to its bank borrowings and may be required to sell some of its holdings to reduce debt and restore coverage at times when it is not advantageous to do so. There is no assurance that a borrowing strategy will be successful. Upon the expiration of the term of the Fund’s existing credit arrangement, the lender may not be willing to extend further credit to the Fund or may only be willing to do so at an increased cost to the Fund. If the Fund is not able to extend its credit arrangement, it may be required to liquidate holdings to repay amounts borrowed from the lender. Each Fund also may borrow for temporary purposes (such as to satisfy redemption requests, to remain fully invested in anticipation of expected cash inflows and settle transactions). Fund borrowings may be equal to as much as 50% of the value of its net assets (not including such borrowings). The Fund is authorized to participate in non-recourse lending programs. The Fund intends to limit its cumulative net investment in such program assets to 5% of its total net assets determined at the time of investment.

As prescribed by applicable regulations, Government Obligations Fund and Short Duration Government Income Fund will be required to maintain a specified level of asset coverage with respect to any bank borrowing immediately following any such borrowing. The Fund may be required to dispose of investments on unfavorable terms if market fluctuations or other factors reduce the required asset coverage to less than the prescribed amount. The Fund may be required to maintain continuous asset coverage levels that are more restrictive than the provisions of the 1940 Act in connection with borrowings or to pay a commitment or other fee to maintain a line of credit. The rights of the lender to receive payments of interest and repayments of principal of any borrowings made by the Fund under a credit facility are senior to the rights of holders of shares, with respect to the payment of dividends or upon liquidation. In the event of a default under a credit arrangement, the lenders may have the right to cause a liquidation of the collateral (i.e., sell Fund assets) and, if any such default is not cured, the lenders may be able to control the liquidation as well.

Illiquid Securities.  The Fund may not invest more than 15% of its net assets in illiquid securities, which may be difficult to value properly and may involve greater risks than liquid securities.  Illiquid securities include those legally restricted as to resale (such as those issued in private placements), and may include securities eligible for resale pursuant to Rule 144A thereunder.  Certain Rule 144A securities may be treated as liquid securities if the investment adviser determines that such treatment is warranted.  Even if determined to be liquid, holdings of these securities may increase the level of Fund illiquidity if eligible buyers become uninterested in purchasing them.

Investing in the Portfolios.  Because the advisory fee paid by each Portfolio differs, a Fund that invests in more than one Portfolio has the potential for a conflict of interest with the investment adviser in that assets could be allocated to a Portfolio for the reason that it has a higher advisory fee. However, in making allocation determinations, the portfolio manager must make determinations on the basis of the best interests of the Fund and its shareholders and under no circumstances are assets allocated to a Portfolio solely because it pays a higher advisory fee .  The Fund may be one of several investors in a Portfolio.  Actions taken by other investors may adversely affect the Fund and its shareholders.

Portfolio Turnover.  The annual portfolio turnover rate of the Fund may exceed 100%.  A mutual fund with a high turnover rate (100% or more) may generate more capital gains and pay more commissions (which may reduce return) than a fund with a lower rate.  Capital gains distributions will be made to shareholders if offsetting capital loss carry forwards do not exist.

General.   Unless otherwise stated, the Fund's investment objective(s) and certain other policies may be changed without shareholder approval. For Government Obligations, High Income Opportunities and Short Duration Government Income Funds, any proposed material change in the investment objective will be submitted to shareholders for their approval. For Income Fund of Boston, shareholders will receive 60 days' written notice of any material change in the investment objectives. During unusual market conditions, the Fund may invest up to 100% of its assets in cash or cash equivalents temporarily, which may be inconsistent with its investment objective(s) and other policies. The Fund might not use all of the strategies and techniques or invest in all of the types of securities described in this Prospectus or the Statement of Additional Information. While at times the Fund may use alternative investment strategies in an effort to limit its losses, it may choose not to do so.

The Fund’s 80% Policy or 90% Policy (as applicable) will not be changed unless shareholders are given at least 60 days' advance written notice of the change and, for the purpose of such policy, net assets include any assets purchased with borrowings for investment purposes.

Eaton Vance Fixed Income Funds

29

Prospectus dated March 1, 2014

Management and Organization

Management.  Each Portfolio’s investment adviser is Boston Management and Research (“BMR”), an indirect subsidiary of Eaton Vance Corp. (“EVC”).  Eaton Vance Management (“Eaton Vance ”) is a wholly-owned subsidiary of EVC.  Eaton Vance and BMR have offices at Two International Place Boston, MA 02110.  Eaton Vance serves as investment adviser to Short Duration Government Income Fund.  Eaton Vance has been managing assets since 1924 and managing mutual funds since 1931.  Eaton Vance and its affiliates currently manage over $ 280 billion on behalf of mutual funds, institutional clients and individuals.   Each investment adviser manages investments pursuant to an investment advisory agreement.  Each Fund is allocated its pro rata share of the advisory fee paid by the Portfolio(s) in which it invests.  Information about portfolio managers and advisory fees is set forth below.

Boston Income Portfolio.  Under its investment advisory agreement with Boston Income Portfolio, BMR receives a monthly advisory fee equivalent to 0.625% annually of the average daily net assets of the Portfolio throughout the month.  Income Fund of Boston is allocated its pro rata share of the advisory fee paid by the Portfolio.  BMR has contractually agreed to reduce its advisory fee as follows:  

These contractual fee reductions cannot be terminated or decreased without the approval of the Portfolio’s Board of Trustees and its shareholders and are intended to continue indefinitely.  For the fiscal year ended October 31, 2013 , the effective annual rate of investment advisory fee paid to BMR, based on average daily net assets of the Portfolio was 0. 56 %.

Michael Weilheimer manages the Boston Income Portfolio.  Mr. Weilheimer managed Income Fund of Boston from January 1, 1996 to inception of the Portfolio.  Mr. Weilheimer manages other Eaton Vance funds and portfolios, and has been a Vice President of Eaton Vance and BMR for more than five years.

Government Obligations Portfolio.  Under Government Obligations Portfolio’s investment advisory agreement, BMR receives a monthly advisory fee equal to 0.75% annually of the average daily net assets of the Portfolio up to $500 million.  On net assets of $500 million or more, BMR has contractually agreed to reduce its advisory fee as follows:

These contractual fee reductions cannot be terminated or decreased without the express consent of the Portfolio’s Board of Trustees and its shareholders and are intended to continue indefinitely.  For the fiscal year ended October 31, 2013 , the effective annual rate of investment advisory fee paid to BMR, based on average daily net assets of the Portfolio was 0. 71 %.  

Susan Schiff is portfolio manager of Government Obligations Portfolio.  Ms. Schiff has managed the Portfolio since it commenced operations.  Ms. Schiff is a Vice President of Eaton Vance and BMR and manages other Eaton Vance portfolios.  

Eaton Vance Fixed Income Funds

30

Prospectus dated March 1, 2014

High Income Opportunities Portfolio.  Under High Income Opportunities Portfolio’s investment advisory agreement, BMR receives a monthly advisory fee equal to the aggregate of a daily asset based fee and a daily income based fee.  The fees are applied on the basis of the following categories:

For the fiscal year ended October 31, 2013 , the effective annual rate of investment advisory fee paid to BMR, based on average daily net assets of the Portfolio was 0. 49 %.

Michael Weilheimer manages High Income Opportunities Portfolio.  Mr. Weilheimer has managed the Portfolio since January 1, 1996.  Additional information about Mr. Weilheimer appears under “Boston Income Portfolio” above.

Short-Term U.S. Government Portfolio.  Under the Portfolio’s investment advisory agreement, BMR receives a monthly advisory fee equal to 0.50% annually of the average daily net assets of the Portfolio. For the fiscal year ended October 31, 2013 , the effective annual rate of investment advisory fee paid to BMR, based on average daily net assets of the Portfolio was 0.50%.  Susan Schiff is portfolio manager of the Portfolio.  Additional information about Ms. Schiff appears under “Government Obligations Portfolio” above.

Short Duration Government Income Fund.  Under the Fund’s investment advisory and administrative agreement, Eaton Vance receives a monthly fee equivalent to 0.15% annually of the average daily net assets of the Fund.  Eaton Vance and the Fund entered into a fee reduction agreement pursuant to which Eaton Vance agreed to waive its annual advisory and administration fee in its entirety.  This fee waiver cannot be eliminated or decreased without the approval of the Fund’s Board of Trustees and shareholders and is intended to continue indefinitely.  The Fund pays its allocable share of the advisory fees and other expenses of the Portfolios in which it invests.  Of this amount, for the fiscal year ended October 31, 2013 , the Fund’s effective annual advisory fees, based on average daily net assets of the Portfolios, was 0. 53 %.

Susan Schiff is portfolio manager of Short Duration Government Income Fund.  Ms. Schiff has managed or co-managed the Fund since it commenced operations. Additional information about Ms. Schiff appears under “Government Obligations Portfolio” above.

Each Fund’s semiannual report provides information regarding the basis for the Trustees’ approval of the investment advisory agreement with regard to Short Duration Government Income Fund and each Portfolio.

The Statement of Additional Information provides additional information about each portfolio manager’s compensation, other accounts managed by each portfolio manager, and each portfolio manager’s ownership of Fund shares.

Eaton Vance serves as the administrator of each Fund, providing each Fund with administrative services and related office facilities.  Eaton Vance does not currently receive a fee for serving as administrator.

Eaton Vance also serves as the sub-transfer agent for each Fund.  For the sub-transfer agency services it provides, Eaton Vance receives an aggregate fee based upon the actual expenses it incurs for its sub-transfer agency services.  This fee is paid to Eaton Vance by a Fund’s transfer agent from the fees the transfer agent receives from the funds sponsored by the Eaton Vance organization (“Eaton Vance funds”).

Organization.   Each Fund, except Income Fund of Boston is a series of Eaton Vance Mutual Funds Trust . Income Fund of Boston is a series of Eaton Vance Series Trust II. Eaton Vance Mutual Funds Trust and Eaton Vance Series Trust II are Massachusetts business trusts.   Each Fund offers multiple classes of shares.  Each Class represents a pro rata interest in a Fund but is subject to different expenses and rights.  The Funds do not hold annual shareholder meetings but may hold special meetings for matters that require shareholder approval (such as electing or removing trustees, approving management or advisory contracts or changing investment policies that may only be changed with shareholder approval).  

As a Portfolio investor, a Fund may be asked to vote on certain Portfolio matters (such as changes in certain Portfolio investment restrictions).  When necessary, a Fund will hold a meeting of its shareholders to consider Portfolio matters and then vote its interest in the Portfolio in proportion to the votes cast by its shareholders.  There may be other Portfolio investors in addition to a

Eaton Vance Fixed Income Funds

31

Prospectus dated March 1, 2014

Fund.  Purchase and redemption activities by other Portfolio investors may impact the management of a Portfolio and its ability to achieve its objective(s).  Each Fund can withdraw its Portfolio investment at any time without shareholder approval.

Because the Funds use this combined Prospectus, a Fund could be held liable for a misstatement or omission made about another Fund.