Report of Foreign Issuer (6-k)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16 OR 15D-16 OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of September 2017

Commission File Number 001-35298

OCEAN RIG UDW INC.

Ocean Rig Cayman Management Services SEZC Limited

3rd Floor Flagship Building

Harbour Drive, Grand Cayman, Cayman Islands

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F [X] Form 40-F [ ]

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): [ ].

Note : Regulation S-T Rule 101(b)(1) only permits the submission in paper of a Form 6-K if submitted solely to provide an attached annual report to security holders.

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): [ ].

Note : Regulation S-T Rule 101(b)(7) only permits the submission in paper of a Form 6-K if submitted to furnish a report or other document that the registrant foreign private issuer must furnish and make public under the laws of the jurisdiction in which the registrant is incorporated, domiciled or legally organized (the registrant's "home country"), or under the rules of the home country exchange on which the registrant's securities are traded, as long as the report or other document is not a press release, is not required to be and has not been distributed to the registrant's security holders, and, if discussing a material event, has already been the subject of a Form 6-K submission or other Commission filing on EDGAR.

INFORMATION CONTAINED IN THIS FORM 6-K REPORT

Attached to this Report on Form 6-K as Exhibit 99.1 is Amendment No. 1 to the Amended and Restated Rights Agreement by and between Ocean Rig UDW Inc. and American Stock Transfer & Trust Company, LLC, dated as of September 20, 2017 (the "Amendment"). The Amendment was made in connection with the Company's ongoing restructuring and has the effect of terminating the Rights Agreement on the date on which the Company notifies the Rights Agent that all of the Restructuring Support Agreement Conditions (as defined in the explanatory statement issued by each of the Scheme Companies dated 21 July 2017 pursuant to Order 102, Rule 20(4) of the Cayman Islands Grand Court Rules 1995 (Revised Edition) (the "Explanatory Statement"), other than the termination of the Rights Agreement, have been satisfied or waived pursuant to the Scheme (as defined in the Explanatory Statement).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.