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 811-21321
                                     -----

Pioneer Municipal High Income Trust
----------------------------------------------------
(Exact name of registrant as specified in charter)

60 State Street Boston, MA  02109
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(Address of principal executive offices)

Terrence J. Cullen
60 State Street
Boston, MA  02109
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(Name and address of agent for service)

Registrant's telephone number, including area code:  (617) 742-7825

Date of fiscal year end:  April 30

Date of reporting period:  July 1, 2009 to June 30, 2010

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)  Pioneer Municipal High Income Trust

By (Signature and Title)  /s/ John F. Cogan, Jr.
                         -------------------------
                         John F. Cogan, Jr., Chairman and President

Date  August 19, 2010
      ----------------

===================== PIONEER MUNICIPAL HIGH INCOME TRUST ======================


DELTA AIR LINES, INC.

Ticker:       DAL            Security ID:  247361702
Meeting Date: JUN 30, 2010   Meeting Type: Annual
Record Date:  MAY 3, 2010

#     Proposal                                Mgt Rec   Vote Cast    Sponsor
1     Elect Director Richard H. Anderson      For       For          Management
2     Elect Director Edward H. Bastian        For       For          Management
3     Elect Director Roy J. Bostock           For       For          Management
4     Elect Director John S. Brinzo           For       For          Management
5     Elect Director Daniel A. Carp           For       For          Management
6     Elect Director John M. Engler           For       For          Management
7     Elect Director Mickey P. Foret          For       For          Management
8     Elect Director David R. Goode           For       For          Management
9     Elect Director Paula Rosput Reynolds    For       For          Management
10    Elect Director Kenneth C. Rogers        For       For          Management
11    Elect Director Rodney E. Slater         For       For          Management
12    Elect Director Douglas M. Steenland     For       For          Management
13    Elect Director Kenneth B. Woodrow       For       For          Management
14    Ratify Auditors                         For       For          Management
15    Provide for Cumulative Voting           Against   For          Shareholder


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VALLEY HEALTH SYSTEM CALIF HOSP

Ticker:                      Security ID:  919676AF3
Meeting Date: JAN 22, 2010   Meeting Type: Written Consent
Record Date:

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

========== END NPX REPORT