MASSACHUSETTS FINANCIAL SERVICES COMPANY
              500 Boylston Street, Boston, Massachusetts 02116-3741
                                 617 - 954-5000




                                        March 16, 2007

VIA EDGAR
United States Securities & Exchange Commission
100 F Street, N.E.
Washington, DC  20549

     Re:  Request for  Withdrawal  of  Registration  Statement  on Form N-14 for
          MFS(R)   Municipal  Series  Trust  File  No.   333-141302;   Accession
          No.0000950156-07-000173

Ladies and Gentlemen:

     Pursuant to Rule 477 under the  Securities  Act of 1933,  the MFS Municipal
Series  Trust   ("Registrant"),   on  behalf  of  MFS  Municipal   Income  Fund,
respectfully   requests  that  the  Securities  and  Exchange   Commission  (the
"Commission")  consent  to the  withdrawal  of the  above  captioned  Form  N-14
Registration  Statement (File No. 333-141302) filed with the Commission at 17:26
PM on March 14, 2007 (the "Registration Statement").

     This  request  for   withdrawal  is  being  made  because  the   Registrant
inadvertently  submitted the registration statement as a Form N-14 filing rather
than a Form  N-14/A  filing.  No  securities  were sold in  connection  with the
Registration Statement.

     Registrant  respectfully  submits  that a  withdrawal  of the  Registration
Statement is consistent with the public interest and the protection of investors
in light of the  circumstances  described  above.  Any questions  regarding this
matter may be directed to Claudia Murphy at  617-954-5406  or the undersigned at
617-954-5843.

                                        Sincerely,



                                        BRIAN E. LANGENFELD
                                        Brian E. Langenfeld
                                        Counsel