MFS® INVESTMENT MANAGEMENT

500 BOYLSTON STREET, BOSTON, MASSACHUSETTS  02116-3741

(617) 954-5000

January 4, 2010

VIA EDGAR

United States Securities and Exchange Commission

100 F Street, N.E.

Washington, DC  20549

Re: MFS® Series Trust IV (the “Trust”) (File Nos. 2-54607 and 811-2594) on behalf of MFS® Government Money Market Fund, MFS® Money Market Fund and MFS® Mid Cap Growth 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 the Prospectuses and Statements of Additional Information for the Funds do not differ from those contained in Post-Effective Amendment No. 50 (the “Amendment”) to the Trust’s Registration Statement on Form N-1A.  This Amendment was filed electronically on December 28, 2009.

Please call the undersigned at (617) 954-5064 or Keli Jean Davis at (617) 954-5873 with any questions you may have.

Very truly yours,

TIMOTHY M. FAGAN

Timothy M. Fagan

Vice President & Senior Counsel

TMF/bjn