MFS® INVESTMENT MANAGEMENT

500 BOYLSTON STREET, BOSTON, MASSACHUSETTS  02116-3741

(617) 954-5000

January 3, 2011

VIA EDGAR

United States Securities & Exchange Commission

100 F Street, N.E.

Washington, DC  20549

Re: MFS® Series Trust I (the “Trust”) (File No.  33-7638 and 811-4777) on Behalf of MFS® Cash Reserve Fund, MFS® Core Equity Fund, MFS® Core Growth Fund, MFS® New Discovery Fund, MFS® Research International Fund, MFS® Technology Fund and MFS® Value Fund (the “Funds”)

Ladies and Gentlemen:

Pursuant to Rule 497(j) under the Securities Act of 1933, as amended, please accept this letter on behalf of the Trust, as certification that Prospectuses and Statements of Additional Information for the Trust do not differ from those contained in Post-Effective Amendment No. 57 (the “Amendment”) to the Trust’s Registration Statement on Form N-1A.  The Amendment was filed electronically on December 28, 2010.

Please call the undersigned at (617) 954-5822 or Matthew Mills at (617) 954-6559 with any questions you may have.

Very truly yours,

CHRISTOPHER R. BOHANE

Christopher R. Bohane

Senior Counsel

CRB/bjn