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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 811-02464

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

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

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                              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

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

               Date of fiscal year end: April 30 and October 31*

             Date of reporting period: July 1, 2017 - June 30, 2018

* MFS Inflation-Adjusted  Bond Fund, a  series of the  Registrant, has a  fiscal
  year end  of October  31. The  fiscal year  ends of  the remaining series of
  the Registrant are April 30.

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ITEM 1.  PROXY VOTING RECORD.



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

ICA File Number: 811-02464
Reporting Period: 07/01/2017 - 06/30/2018
MFS Series Trust IX









=========================== MFS Corporate Bond Fund ============================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: DEC 08, 2017   Meeting Type: Written Consent
Record Date:  DEC 08, 2017

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Amend Fundamental Investment            For       For          Management
      Restriction Regarding Industry
      Concentration




====================== MFS Inflation - Adjusted Bond Fund ======================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: DEC 08, 2017   Meeting Type: Written Consent
Record Date:  DEC 08, 2017

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Amend Fundamental Investment            For       For          Management
      Restriction Regarding Industry
      Concentration




========================== MFS Limited Maturity Fund ===========================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: DEC 08, 2017   Meeting Type: Written Consent
Record Date:  DEC 08, 2017

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Amend Fundamental Investment            For       For          Management
      Restriction Regarding Industry
      Concentration




===================== MFS Municipal Limited Maturity Fund ======================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: DEC 08, 2017   Meeting Type: Written Consent
Record Date:  DEC 08, 2017

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Amend Fundamental Investment            For       For          Management
      Restriction Regarding Industry
      Concentration




========================== MFS Total Return Bond Fund ==========================


MFS SERIES TRUST XIV - MFS INSTITUTIONAL MONEY MARKET PORTFOLIO

Ticker:                      Security ID:  55291X109
Meeting Date: DEC 08, 2017   Meeting Type: Written Consent
Record Date:  DEC 08, 2017

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Amend Fundamental Investment            For       For          Management
      Restriction Regarding Industry
      Concentration

========== 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 SERIES TRUST IX

By (Signature and Title):  David DiLorenzo*
                           ------------------------------------------
                           David DiLorenzo, President and Principal
                           Executive Officer

Date: August 28, 2018

*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.