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THE MFS SERIES TRUST
500 Boylston Street Boston Massachusetts 02116-3741
617 954 5000
May 7, 1997
VIA EDGAR
Securities and Exchange Commission
Judiciary Plaza
450 Fifth Street, NW
Washington, DC 20549
Re: The MFS Series Trust (the "Trust") (File No. 33-64010) on
behalf of MFS Aggressive Small Cap Equity Fund
Ladies and Gentlemen:
Pursuant to Rule 497(j) under the Securities Act of 1933, as amended,
please accept this letter as certification that the Prospectus and Statement of
Additional Information for the Trust do not differ from those contained in
Post-Effective Amendment No. 8 (the "Amendment") to the Trust's Registration
Statement on Form N-1A. The Amendment was filed electronically on April 30,
1997.
Please call the undersigned or Annamarie D'Angelo at (617) 954-5180 or
(800) 343-2829 with any questions you may have.
Very truly yours,
JAMES F. DESMARAIS
James F. DesMarais
Assistant Secretary Pro Tempore
JFD/bjn