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                                 UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                   FORM N-PX

                    ANNUAL REPORT OF PROXY VOTING RECORD OF
                   REGISTERED MANAGEMENT INVESTMENT COMPANIES

                  Investment Company Act file number 811-4096

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

               500 Boylston Street, Boston, Massachusetts  02116
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              (Address of principal executive offices) (Zip code)

                                Susan S. Newton
                    Massachusetts Financial Services Company
                              500 Boylston Street
                          Boston, Massachusetts  02116
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                    (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

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             Date of reporting period: July 1, 2010 - June 30, 2011

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ITEM 1.  PROXY VOTING RECORD.

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

ICA File Number: 811-04096
Reporting Period: 07/01/2010 - 06/30/2011
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 FLORIDA 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 ===========================


SMURFIT-STONE CONTAINER CORPORATION

Ticker:       SSCC           Security ID:  83272A104
Meeting Date: MAY 27, 2011   Meeting Type: Special
Record Date:  APR 08, 2011

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Approve Merger Agreement                For       For          Management
2     Adjourn Meeting                         For       For          Management


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SUMNER COUNTY TENN

Ticker:                      Security ID:  86642PDK0
Meeting Date: JUN 16, 2011   Meeting Type: Written Consent
Record Date:  APR 26, 2011

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     The Plan                                None      For          Management


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WEST POINT VIRGINIA INDUS DEV AUTH SOLID WASTE

Ticker:                      Security ID:  955489AE9
Meeting Date: MAR 22, 2011   Meeting Type: Written Consent
Record Date:  FEB 15, 2011

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     To Accept The Plan                      For       For          Management
2     Opt Out Release                         For       For          Management


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YONKERS N Y INDL

Ticker:                      Security ID:  986083BG7
Meeting Date: SEP 03, 2010   Meeting Type: Written Consent
Record Date:  MAY 27, 2010

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Undersigned Hereby Approves To Waive    For       For          Management
      Long-term Debt Service Coverage Ratio
      For St. John's Riverside Hospital For
      Fiscal Year 2009, Consents To And
      Directs The Trustee To Waive Such
      Longterm Debt Service Coverage Ratio &
      To Execute First Supplemental




======================= MFS NEW YORK MUNICIPAL BOND FUND =======================


YONKERS N Y INDL

Ticker:                      Security ID:  986083BH5
Meeting Date: SEP 03, 2010   Meeting Type: Written Consent
Record Date:  MAY 27, 2010

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Undersigned Hereby Approves To Waive    For       For          Management
      Long-term Debt Service Coverage Ratio
      For St. John's Riverside Hospital For
      Fiscal Year 2009, Consents To And
      Directs The Trustee To Waive Such
      Longterm Debt Service Coverage Ratio &
      To Execute First Supplemental




==================== 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 =======================


SUMNER COUNTY TENN

Ticker:                      Security ID:  86642PDK0
Meeting Date: JUN 16, 2011   Meeting Type: Written Consent
Record Date:  APR 26, 2011

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     The Plan                                None      For          Management




======================= MFS VIRGINIA MUNICIPAL BOND FUND =======================


SMURFIT-STONE CONTAINER CORPORATION

Ticker:       SSCC           Security ID:  83272A104
Meeting Date: MAY 27, 2011   Meeting Type: Special
Record Date:  APR 08, 2011

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Approve Merger Agreement                For       For          Management
2     Adjourn Meeting                         For       For          Management


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WEST POINT VIRGINIA INDUS DEV AUTH SOLID WASTE

Ticker:                      Security ID:  955489AE9
Meeting Date: MAR 22, 2011   Meeting Type: Written Consent
Record Date:  FEB 15, 2011

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     To Accept The Plan                      For       For          Management
2     Opt Out Release                         For       For          Management




==================== 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):  MARIA F. DIORIODWYER*
                           -----------------------------------------------------
                           Maria F. DiOrioDwyer, Principal Executive Officer

Date:  August  12,  2011

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

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*    Executed by Susan S. Newton on behalf of Maria F. DiOrioDwyer pursuant to a
     Power of Attorney dated October 26, 2010. (1)

(1)  Incorporated by reference to MFS Series Trust XIII (File Nos. 2-74959 and
     811-3327) Post-Effective Amendment No. 45 filed with the SEC via EDGAR on
     March 10, 2011.