OMB APPROVAL OMB Number: 3235-0578 Expires: April 30, 2010 Estimated average burden hours per response..... 10.5 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM N-Q CERTIFIED SHAREHOLDER REPORT 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 (Address of principal executive offices) (ZIP code) Dorothy E. Bourassa, Pioneer Investment Management, Inc., 60 State Street, Boston, MA 02109 (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 31, 2009 Form N-Q is to be used by management investment companies, other than small business investment companies registered on Form N-5 (239.24 and 274.5 of this chapter), to file reports with the Commission, not later than 60 days after close of the first and third fiscal quarters, pursuant to Rule 30b1-5under the Investment Company Act of 1940 (17 CFR 270.30b-5). The Commission may use the information provided on Form N-Q in its regulatory, disclosure review, inspection, and policymaking roles. A registrant is required to disclose the information specified by Form N-Q, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-Q unless the Form displays a currently valid Office of Management and Budget ("OMB") control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. ss. 3507. ITEM 1. Schedule of Investments. Pioneer Municipal High Income Trust SCHEDULE OF INVESTMENTS 7/31/09 (unaudited) Principal Amount ($) Value ($) TAX EXEMPT OBLIGATIONS - 130.4% of Net Assets Alabama - 0.8% 1,000,000 Huntsville-Redstone Village Special Care Facilities 727,580 2,000,000 Huntsville-Redstone Village Special Care Facilities1,303,940 2,031,520 Arizona - 2.2% 5,000,000 Apache County Industrial Development Authority, 5.84,536,450 970,000 Pima County Industrial Development Authority, 7.25% 768,347 500,000 Yavapai County Industrial Development Authority, 6. 464,680 5,769,477 California - 10.7% 7,885,000 (a) California State University Revenue, RIB, 9.532%, 17,279,511 4,500,000 California Statewide Communities Development Authority Environmental Facilities Revenue, 9.0%, 12/1/38 3,593,610 1,000,000 California Statewide Communities Development Author 827,730 5,150,000 + Golden State Tobacco Securitization Corp., 7.8%, 6/6,301,231 7,000,000 + Golden State Tobacco Securitization Corp., 7.875%, 8,583,260 1,000,000 University of California Revenue, 5.0%, 5/15/25 1,014,040 655,000 Valley Health System Hospital Revenue, 6.5%, 5/15/2 360,119 27,959,501 Connecticut - 5.4% 10,335,000(a) Connecticut Health & Educational Facilities Authori10,804,416 5,000,000 Mohegan Tribe Indians Gaming Authority, 6.25%, 1/1/3,356,750 14,161,166 Delaware - 0.4% 765,000 Sussex County Delaware Revenue, 5.9%, 1/1/26 607,723 600,000 Sussex County Delaware Revenue, 6.0%, 1/1/35 434,646 1,042,369 District of Columbia - 3.5% 5,000,000 District of Columbia Tobacco Settlement Financing C4,230,000 6,000,000 District of Columbia Tobacco Settlement Financing C5,025,060 9,255,060 Florida - 5.4% 1,700,000 Beacon Lakes Community Development, 6.9%, 5/1/35 1,227,281 2,000,000 Brevard County Health Facilities Authority Revenue,1,561,420 2,445,000 Liberty County Subordinate Revenue, 8.25%, 7/1/28 2,045,756 2,500,000 Miami-Dade County Aviation Revenue, 5.5%, 10/1/41 2,426,450 1,000,000 St. Johns County Industrial Development Authority R 710,910 2,000,000 St. Johns County Industrial Development Authority R1,272,640 5,000,000 Tallahassee Health Facilities Revenue, 6.375%, 12/14,849,400 14,093,857 Georgia - 2.6% 4,240,000 (a) Atlanta Georgia Water & Waste Revenue, RIB, 9.03%, 3,779,705 2,400,000 Fulton County Residential Care Facilities Revenue, 1,709,856 1,100,000 Fulton County Residential Care Facilities Revenue, 668,063 1,000,000 Rockdale County Development Authority Revenue, 6.12 719,200 6,876,824 Idaho - 1.8% 5,000,000 Power County Industrial Development Corp., 6.45%, 84,605,650 Illinois - 9.8% 2,000,000 (b) Centerpoint Intermodal Center, 10.0%, 6/15/23 (144A1,040,600 12,000,000 Chicago O'Hare International Airport Special Facili4,443,600 1,000,000 Illinois Finance Authority Revenue, 6.0%, 11/15/27 760,840 2,000,000 Illinois Finance Authority Revenue, 6.0%, 8/15/39 2,066,940 4,000,000 Illinois Finance Authority Revenue, 6.0%, 11/15/39 2,722,800 1,500,000 (c) Illinois Health Facilities Authority Revenue, 6.9%, 660,900 16,880,000(d) Metropolitan Pier & Exposition Authority Dedicated 12,771,914 1,800,000 Southwestern Illinois Development Authority Revenue1,160,406 25,628,000 Indiana - 4.5% 5,000,000 Indiana Health & Educational Facility Financing Aut4,203,300 1,000,000 Indiana State Development Finance Authority Revenue 921,790 4,300,000 Indiana State Development Finance Authority Revenue4,134,235 2,500,000 (b) Rockport Pollution Control Revenue, 6.25%, 6/1/25 2,614,025 11,873,350 Louisiana - 2.0% 1,500,000 Louisiana Local Government Environmental Facilities1,247,670 5,000,000 Louisiana Public Facilities Authority Revenue, 5.5%4,027,400 5,275,070 Massachusetts - 4.5% 2,385,000 Massachusetts Development Finance Agency Revenue, 71,855,387 1,000,000 Massachusetts Educational Financing Authority Reven1,011,520 3,500,000 Massachusetts Health & Educational Facilities Autho3,276,105 2,500,000 Massachusetts Health & Educational Facilities Autho1,805,700 5,000,000 Massachusetts Health & Educational Facilities Autho3,854,300 11,803,012 Michigan - 3.5% 950,000 Doctor Charles Drew Academy, 5.7%, 11/1/36 517,949 1,525,000 Flint Michigan Hospital Building Authority Revenue,1,297,058 1,500,000 John Tolfree Health System Corp., 6.0%, 9/15/23 1,177,215 2,000,000 Michigan State Hospital Finance Authority Revenue, 1,384,240 5,830,000 Michigan Tobacco Settlement Finance Authority, 6.0%3,517,530 1,470,000 Star International Academy Certificates of Particip1,126,814 9,020,806 Minnesota - 0.6% 1,675,000 Duluth Economic Development Authority Health Care F1,512,391 Mississippi - 1.0% 3,000,000 Mississippi Business Finance Corp. Pollution Contro2,726,640 Montana - 0.1% 1,600,000 (c) Two Rivers Authority, Inc. Correctional Facility Im 312,304 Nebraska - 0.5% 2,000,000 Grand Island Solid Waste Disposal Facilities Revenu1,362,080 Nevada - 0.0% 2,000,000 (c) Nevada State Department of Business & Industry, 7.2 100,000 New Jersey - 12.2% 2,000,000 New Jersey Economic Development Authority Revenue, 1,541,220 13,350,000 New Jersey Economic Development Authority Revenue, 9,143,415 1,000,000 New Jersey Economic Development Authority Revenue, 737,560 6,150,000 (b) New Jersey Economic Development Authority Revenue, 4,583,964 10,370,000 New Jersey Transportation Trust Fund Authority, 0.03,759,229 10,000,000 + Tobacco Settlement Financing Corp., 6.75%, 6/1/39 12,043,800 31,809,188 New Mexico - 1.3% 1,500,000 Otero County New Mexico Project Revenue, 6.0%, 4/1/1,184,700 2,960,000 Otero County New Mexico Project Revenue, 6.0%, 4/1/2,206,473 3,391,173 New York - 8.6% 2,500,000 Albany New York Industrial Development Agency Civic2,130,150 3,000,000 Dutchess County Industrial Development Agency Reven2,799,420 1,000,000 Nassau County New York Industrial Development Agenc 766,510 2,000,000 New York City Industrial Development Agency, 5.375%1,794,860 990,000 New York City Industrial Development Agency, 6.9%, 398,831 7,040,000 (a) New York State Dormitory Authority Revenue, RIB, 128,727,277 2,000,000 Suffolk County Industrial Development Agency, 7.25%1,678,580 4,000,000 Triborough Bridge & Tunnel Authority Revenue, 5.25%4,070,280 22,365,908 North Carolina - 2.8% 4,530,000 Charlotte North Carolina Special Facilities Revenue2,753,470 5,740,000 Charlotte North Carolina Special Facilities Revenue4,477,257 7,230,727 Oklahoma - 3.7% 4,500,000 + Oklahoma Development Finance Authority Revenue, 5.64,553,955 1,225,000 Tulsa Municipal Airport Revenue, 6.25%, 6/1/20 893,209 4,350,000 Tulsa Municipal Airport Revenue, 7.35%, 12/1/11 4,113,795 9,560,959 Pennsylvania - 8.9% 3,000,000 Allegheny County Hospital Development Authority Rev1,910,310 1,550,000 Allegheny County Hospital Development Authority Rev1,323,948 12,300,000 + Allegheny County Hospital Development Authority Rev13,894,080 1,000,000 Columbia County Hospital Authority Health Care Reve 715,510 845,000 Hazleton Health Services Authority Hospital Revenue 727,106 1,280,000 Langhorne Manor Borough Higher Education & Health A 921,485 5,000,000 Pennsylvania Economic Development Financing Authority Solid Waste Disposal Revenue, 6.0%, 6/1/31 3,212,400 500,000 Pennsylvania Higher Educational Facilities Authorit 446,115 23,150,954 Rhode Island - 1.6% 6,000,000 Central Falls Detention Facilities Revenue, 7.25%, 4,171,200 South Carolina - 2.6% 5,185,000 + South Carolina Jobs Economic Development Authority 5,955,284 665,000 + South Carolina Jobs Economic Development Authority 771,500 6,726,784 Tennessee - 5.2% 7,000,000 + Johnson City Health & Educational Facilities Board 7,974,610 2,480,000 Knox County Health, Educational & Housing Facilities Board Hospital Revenue, 6.375%, 4/15/22 2,525,012 4,600,000 Sullivan County Health, Educational & Housing Facilities Board Hospital Revenue, 5.25%, 9/1/36 3,132,508 13,632,130 Texas - 14.4% 1,345,000 Bexar County Housing Finance Corp., 8.0%, 12/1/36 992,179 1,000,000 Dallas-Fort Worth International Airport Revenue, 6. 480,750 4,000,000 Decatur Hospital Authority Revenue, 7.0%, 9/1/25 3,466,200 2,000,000 Gulf Coast Industrial Development Authority Revenue 878,600 3,750,000 Houston Airport System Special Facilities Revenue, 2,370,750 5,340,000 Lubbock Health Facilities Development Corp.,6.625% 4,025,826 10,000,000 North Texas Tollway Authority Revenue, 5.75%,1/1/3 9,650,600 2,810,000 (a)Northside Independent School District, RIB, 10.778% 2,936,057 500,000 Sabine River Authority Pollution Control Revenue, 6 222,545 7,040,000 (a) Texas State, RIB, 11.59%, 4/1/30 (144A) 7,596,442 1,075,000 Willacy County Local Government Corp. Revenue,6.0% 1,062,154 5,250,000 Willacy County Local Government Corp. Revenue, 6. 3,968,685 37,650,788 Utah - 0.2% 800,000 Spanish Fork City Charter School Revenue, 5.55%, 11 616,776 Vermont - 0.6% 1,500,000 Vermont Educational & Health Buildings Financing Ag1,555,665 Virginia - 0.4% 1,000,000 Peninsula Ports Authority, 6.0%, 4/1/33 970,420 Washington - 8.6% 4,710,000 Spokane Public Facilities District Hotel/Motel Tax 4,924,022 7,025,000 Tobacco Settlement Authority Revenue, 6.625%, 6/1/35,947,716 14,315,000 Washington State General Obligation, 0.0%, 6/1/22 7,987,770 5,000,000 Washington State Housing Finance Committee Nonprofi3,609,700 22,469,208 Wisconsin - 0.0% 2,320,000 Aztalan Wisconsin Exempt Facilities Revenue, 7.5%, 121,800 TOTAL TAX-EXEMPT OBLIGATIONS (Cost $370,184,198) 340,832,757 MUNICIPAL COLLATERALIZED DEBT OBLIGATION - 2.7% of Net Assets 10,000,000(b)(Non-Profit Preferred Funding Trust I,12.0%, 9/15/376,970,800 TOTAL MUNICIPAL COLLATERALIZED DEBT OBLIGATION (Cost $10,000,000) 6,970,800 Shares COMMON STOCK - 0.7% of Net Assets 248,558 (f) Delta Air Lines, Inc. 1,722,507 TOTAL COMMON STOCK (Cost $6,612,756) 1,722,507 TAX-EXEMPT MONEY MARKET MUTUAL FUND - 1.5% of Net Assets 4,000,000 BlackRock Liquidity Funds MuniFund Portfolio 4,000,000 TOTAL TAX-EXEMPT MONEY MARKET MUTUAL FUND (Cost $4,000,000) 4,000,000 TOTAL INVESTMENTS IN SECURITIES - 135.3% (Cost $390,796,954) (g)(h) 353,526,064 OTHER ASSETS AND LIABILITIES - 3.4% 8,814,365 PREFERRED SHARES AT REDEMPTION VALUE, INCLUDING DIVIDENDS PAYABLE - (38.7)% (101,004,219) NET ASSETS APPLICABLE TO COMMON SHAREOWNERS-100.0 261,336,210 RIB Residual Interest Bonds (144A) Security is exempt from registration under Rule 144A of the Securities Act of 1933. Such securities may be resold normally to qualified institutional buyers in a transaction exempt from registration. At July 31, 2009 the value of these securities amounted to $49,751,584 or 19.0% of net assets applicable to common shareowners. + Prerefunded bonds have been collateralized by U.S. Treasury securities or U.S. Government Agencies which are held in escrow to pay interest and principal on the tax exempt issue and to retire the bonds in full at the earliest refunding date. (a) The interest rate is subject to change periodically and inversely based upon prevailing market rates. The interest rate shown is the coupon rate at July 31, 2009. (b) The interest rate is subject to change periodically. The interest rate shown is the coupon rate at July 31, 2009. (c) Security is in default and is non-income producing. (d) Debt obligation initially issued at one coupon which converts to a higher coupon at a specific date. The rate shown is the coupon rate at July 31, 2009. (e) Indicates a security that has been deemed illiquid. The aggregate cost of illiquid securities is $10,000,000. The aggregate value $6,970,800 represents 2.7% of net assets applicable to common shareowners. (f) Non-income producing. (g) The concentration of investments by type of obligation/market sector is as follows: Insured: NATL-RE 8.4% FSA 1.1 MBIA 1.0 ACA 0.9 PSF 0.8 AMBAC 0.3 Revenue Bonds: Health Revenue 30.4 Tobacco Revenue 13.0 Other Revenue 11.8 Airport Revenue 10.9 Pollution Control Revenue 4.4 Facilities Revenue 4.2 Education Revenue 4.0 Development Revenue 3.7 Transportation Revenue 2.8 Utilities Revenue 1.0 Gaming Revenue 1.0 Housing Revenue 0.3 100.0% (h) At July 31, 2009, the net unrealized loss on investments based on cost for federal income tax purposes of $389,042,834 was as follows: Aggregate gross unrealized gain for all investments$17,347,518 there is an excess of value over tax cost Aggregate gross unrealized loss for all investments(52,864,288) there is an excess of tax cost over value ($35,516,770) Net unrealized loss For financial reporting purposes net unrealized loss on investments was $37,270,890 and cost of investments aggregated $390,796,954. Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below. Highest priority is given to Level 1 inputs and lowest priority is given to Level 3. Level 1 - quoted prices in active markets for identical securities Level 2 - other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.) Level 3 - significant unobservable inputs (including the Fund's own assumptions in determining fair value of investments) The following is a summary of the inputs used as of July 31, 2009, in valuing the Fund's assets: Level 1 Level 2 Level 3 Total Municipal bonds $ - $340,832,757 $- $340,832,757 Municipal collateralized debt - 6,970,800 - 6,970,800 Common stock 1,722,507 - - 1,722,507 Temporary cash investments 4,000,000 - - 4,000,000 Total $5,722,507 $347,803,557 $ - $353,526,064 ITEM 2. CONTROLS AND PROCEDURES. (a) Disclose the conclusions of the registrant's principal executive officer or officers and principal financial officer or officers, or persons performing similar functions, about the effectiveness of the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Act (17 CFR 270.30a-3(c))) as of a date within 90 days of the filing date of the report that includes the disclosure required by this paragraph, based on their evaluation of these controls and procedures required by Rule 30a-3(b) under the Act (17 CFR270.30a-3(b))) and Rule 13a-15(b) or 15d-15(b) under the Exchange Act (17 CFR240.13a-15(b) or 240.15d-15(b)). The registrant's principal executive officer and principal financial officer have concluded that the registrant's disclosure controls and procedures are effective based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of this report. (b) Disclose any change in the registrant's internal controls over financial reporting (as defined in Rule 30a-3(d) under the Act (17 CFR270.30a-3(d)) that occurred during the registrant's last fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting. There were no significant changes in the registrant's internal control over financial reporting that occurred during the second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting. ITEM 3. EXHIBITS. (a) A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2 under the Act (17 CFR 270.30a-2). Filed herewith. SIGNATURES [See General Instruction F] Pursuant to the requirements of the Securities Exchange Act of 1934 and 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, President Date September 28, 2009 Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated. By (Signature and Title)* /s/ John F. Cogan, Jr. John F. Cogan, Jr., President Date September 28, 2009 By (Signature and Title)* /s/ Mark Bradley Mark Bradley, Treasurer Date September 28, 2009 * Print the name and title of each signing officer under his or her signature.