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                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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                                    FORM N-PX

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                     ANNUAL REPORT OF PROXY VOTING RECORD OF
                   REGISTERED MANAGEMENT INVESTMENT COMPANIES

                  Investment Company Act file number 811-04096

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                           MFS MUNICIPAL SERIES TRUST
               (Exact name of registrant as specified in charter)

                              --------------------

               111 Huntington Avenue, Boston, Massachusetts 02199
               (Address of principal executive offices) (Zip code)

                              --------------------

                                Susan A. Pereira
                    Massachusetts Financial Services Company
                              111 Huntington Avenue
                           Boston, Massachusetts 02199
                    (Name and address of agents for service)

       Registrant's telephone number, including area code: (617) 954-5000

                              --------------------

                        Date of fiscal year end: March 31

             Date of reporting period: July 1, 2014 - June 30, 2015

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ITEM 1. PROXY VOTING RECORD.



******************************* FORM N-Px REPORT *******************************

ICA File Number: 811-04096
Reporting Period: 07/01/2014 - 06/30/2015
MFS Municipal Series Trust









======================= MFS Alabama Municipal Bond Fund ========================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



======================= MFS Arkansas Municipal Bond Fund =======================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



====================== MFS California Municipal Bond Fund ======================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



======================= MFS Georgia Municipal Bond Fund ========================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



======================= MFS Maryland Municipal Bond Fund =======================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



==================== MFS Massachusetts Municipal Bond Fund =====================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



===================== MFS Mississippi Municipal Bond Fund ======================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



========================== MFS Municipal Income Fund ===========================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



======================= MFS New York Municipal Bond Fund =======================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



==================== MFS North Carolina Municipal Bond Fund ====================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



===================== MFS Pennsylvania Municipal Bond Fund =====================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



==================== MFS South Carolina Municipal Bond Fund ====================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



====================== MFS Tennessee Municipal Bond Fund =======================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



======================= MFS Virginia Municipal Bond Fund =======================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.



==================== MFS West Virginia Municipal Bond Fund =====================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.
========== END NPX REPORT



                                   SIGNATURES

Pursuant to the requirements of the Investment Company Act of 1940, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

Registrant: MFS MUNICIPAL SERIES TRUST

By (Signature and Title):  ROBIN STELMACH*
                           ----------------------------------------------
                           Robin Stelmach, Principal Executive
                           Officer & President

Date: August 26, 2015

*By (Signature and Title)  /s/ Susan A. Pereira
                           ----------------------------------------------
                           Susan A. Pereira, as attorney-in-fact

*    Executed by Susan A. Pereira on behalf of Robin Stelmach pursuant to a
     Power of Attorney dated October 1, 2014. (1)

(1)  Incorporated by reference to MFS Institutional Trust (File Nos. 33-37615
     and 811-06174) Post-Effective Amendment No. 38 filed with the SEC via EDGAR
     on October 27, 2014.