Definitive Materials Filed by Investment Companies. (497)

LOGO

787 Seventh Avenue

New York, NY 10019-6099

Tel: 212 728 8000

Fax: 212 728 8111

December 21, 2012

VIA EDGAR

Securities and Exchange Commission

100 F Street, NE

Washington, DC 20549

Re:

LifePath ^® Active 2015 Portfolio, LifePath ^® Active 2020 Portfolio, LifePath ^® Active 2025 Portfolio, LifePath ^® Active 2030 Portfolio, LifePath ^® Active 2035 Portfolio, LifePath ^® Active 2040 Portfolio, LifePath ^® Active 2045 Portfolio and LifePath ^® Active 2050 Portfolio, each a series of BlackRock Funds II

( File No. 333-142592 and File No. 811-22061)

Ladies and Gentlemen:

On behalf of BlackRock Funds II and pursuant to Rule 497 under the Securities Act of 1933, as amended, attached for filing are exhibits containing interactive data format risk/return summary information that mirrors the risk/return summary information the 497 filing for LifePath ^® Active 2015 Portfolio, LifePath ^® Active 2020 Portfolio, LifePath ^® Active 2025 Portfolio, LifePath ^® Active 2030 Portfolio, LifePath ^® Active 2035 Portfolio, LifePath ^® Active 2040 Portfolio, LifePath ^® Active 2045 Portfolio and LifePath ^® Active 2050 Portfolio (the “Funds”). The purpose of the filing is to submit the 497 filing dated November 30, 2012 in XBRL for the Funds.