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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)

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

                             Christopher R. Bohane
                   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

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                       Date of fiscal year end: March 31

            Date of reporting period: July 1, 2018 - June 30, 2019

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ITEM 1. PROXY VOTING RECORD.



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

ICA File Number: 811-04096
Reporting Period: 07/01/2018 - 06/30/2019
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):  David DiLorenzo*
                           -----------------------------------------
                           David DiLorenzo, President and Principal
                           Executive Officer

Date: August 28, 2019

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

*   Executed by Susan A. Pereira on behalf of David DiLorenzo pursuant to a
    Power of Attorney dated June 1, 2017. (1)

(1) Incorporated by reference to MFS Series Trust XIII (File Nos. 2-74959 and
    811-03327) Post-Effective Amendment No. 65 filed with the SEC via EDGAR on
    June 27, 2017 (accession number 0001104659-17-041693).