c54100_nq.htm -- Converted by SEC Publisher, created by BCL Technologies Inc., for SEC Filing

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED
MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number 811-21036

Name of Fund: BlackRock Municipal Bond Trust (BBK)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Donald C. Burke, Chief Executive Officer, BlackRock Municipal Bond Trust, 800 Scudders Mill Road, Plainsboro, NJ, 08536. Mailing address: P.O. Box 9011, Princeton, NJ, 08543-9011

Registrant’s telephone number, including area code: (800) 882-0052, Option 4

Date of fiscal year end: 08/31/2008

Date of reporting period: 03/01/2008 – 05/31/2008

Item 1 – Schedule of Investments

BlackRock Municipal Bond Trust   
Schedule of Investments May 31, 2008 (Unaudited) 
(Percentages shown are based on Net Assets) 
     
 
 Par  
 
  
State 
 
 Municipal Bonds 
 
 (000 ) 
 
Value 
Alabama - 5.5%    Huntsville, Alabama, Health Care Authority Revenue Bonds, Series A, 
 
    
 
  
 
 
 5.75%, 6/01/11 (a) 
$
7,500  
$
8,188,350 
Arizona - 6.2%    Glendale, Arizona, Municipal Property Corporation, Excise Tax 
 
    
 
  
    Revenue Refunding Bonds, Series A, 4.50%, 7/01/32 
 
 3,655  
 
 3,524,590 
    Salt Verde Financial Corporation, Arizona, Senior Gas Revenue Bonds, 
 
    
 
  
    5%, 12/01/32 
 
 2,545  
 
 2,289,635 
    Salt Verde Financial Corporation, Arizona, Senior Gas Revenue Bonds, 
 
    
 
  
    5%, 12/01/37 
 
 2,565  
 
 2,270,128 
    San Luis, Arizona, Facilities Development Corporation, Senior Lien 
 
    
 
  
    Revenue Bonds (Regional Detention Center Project), 
 
    
 
  
    6.25%, 5/01/15 
 
 300  
 
 285,237 
    San Luis, Arizona, Facilities Development Corporation, Senior Lien 
 
    
 
  
    Revenue Bonds (Regional Detention Center Project), 7%, 5/01/20 
 
 300  
 
 278,475 
    San Luis, Arizona, Facilities Development Corporation, Senior Lien 
 
    
 
  
    Revenue Bonds (Regional Detention Center Project), 
 
    
 
  
    7.25%, 5/01/27 
 
 600  
 
 551,430 
     
 
    
 
 9,199,495 
California - 6.1%    California County Tobacco Securitization Agency, Tobacco Revenue 
 
    
 
  
    Bonds (Stanislaus County Tobacco Funding Corporation), 
 
    
 
  
    Sub-Series C, 6.30%, 6/01/55 (b) 
 
 4,500  
 
 102,060 
    California County Tobacco Securitization Agency, Tobacco Revenue 
 
    
 
  
    Bonds (Stanislaus County Tobacco Funding Corporation), 
 
    
 
  
    Sub-Series D, 7.251%, 6/01/55 (b) 
 
 5,750  
 
 111,837 
    California State, GO, Refunding, 5%, 6/01/32 
 
 2,890  
 
 2,898,294 
    California State, GO, Refunding, 5%, 6/01/34 
 
 1,800  
 
 1,802,178 
    University of California Revenue Bonds, Series B, 4.75%, 5/15/38 
 
 2,660  
 
 2,638,933 
    Val Verde, California, Unified School District Financing Authority, 
 
    
 
  
    Special Tax Refunding Bonds, Junior Lien, 6.25%, 10/01/28 
 
 1,585  
 
 1,584,826 
 
 
  
 
    
 
 9,138,128 
Colorado - 0.9%    Colorado Springs, Colorado, Utilities System Improvement Revenue 
 
    
 
  
    Bonds, Subordinate Lien, Series C, 5%, 11/15/45 (c) 
 
 635  
 
 645,255 
               
Portfolio Abbreviations 
To simplify the listings of BlackRock Municipal Bond Trust's portfolio holdings in the Schedule of Investments,
we have abbreviated the names of many of the securities according to the list below. 
  AMT  Alternative Minimum Tax (subject to)  IDA  Industrial Development Authority 
  EDA  Economic Development Authority  IDR  Industrial Development Revenue Bonds 
  EDR  Economic Development Revenue Bonds  M/F  Multi-Family 
  GO  General Obligation Bonds  S/F  Single-Family 
  HFA  Housing Finance Agency     
         
         
         
         

1

BlackRock Municipal Bond Trust   
Schedule of Investments May 31, 2008 (Unaudited) 
(Percentages shown are based on Net Assets) 
     
 
 Par  
 
  
State 
 
 Municipal Bonds 
 
 (000 ) 
 
Value 
    Park Creek Metropolitan District, Colorado, Senior Limited Tax 
 
    
 
  
    Supported Revenue Refunding Bonds, 5.50%, 12/01/37 
$
635  
$
593,820 
 
 
  
 
    
 
 1,239,075 
District of    District of Columbia Revenue Bonds (Georgetown University), 
 
    
 
  
Columbia - 12.5%    Series A, 6.071%, 4/01/11 (a)(b)(d) 
 
 33,450  
 
 6,210,661 
    District of Columbia, Revenue Refunding Bonds (Friendship Public 
 
    
 
  
    Charter School, Inc.), 5.25%, 6/01/33 (e) 
 
 595  
 
 526,385 
    District of Columbia, Tax Increment Revenue Bonds (Gallery Place 
 
    
 
  
    Project), 5.40%, 7/01/31 (c) 
 
 6,000  
 
 6,240,660 
    District of Columbia Tobacco Settlement Financing Corporation, 
 
    
 
  
    Asset-Backed Revenue Refunding Bonds, 6.75%, 5/15/40 
 
 5,580  
 
 5,610,411 
 
 
  
 
    
 
 18,588,117 
Florida - 18.9%    Halifax Hospital Medical Center, Florida, Hospital Revenue Refunding 
 
    
 
  
    Bonds, Series A, 5%, 6/01/38 
 
 1,535  
 
 1,355,436 
    Martin County, Florida, IDA, IDR, Refunding (Indiantown Cogeneration 
 
    
 
  
    Project), AMT, Series A, 7.875%, 12/15/25 
 
 3,000  
 
 3,006,450 
    Miami Beach, Florida, Health Facilities Authority, Hospital Revenue 
 
    
 
  
    Refunding Bonds (Mount Sinai Medical Center of Florida), 
 
    
 
  
    6.75%, 11/15/21 
 
 2,810  
 
 2,898,656 
    Orange County, Florida, Health Facilities Authority, Hospital Revenue 
 
    
 
  
    Bonds (Adventist Health System), 5.625%, 11/15/12 (a) 
 
 10,000  
 
 11,111,000 
    Orange County, Florida, Tourist Development, Tax Revenue 
 
    
 
  
    Refunding Bonds, 4.75%, 10/01/32 (f) 
 
 1,845  
 
 1,762,861 
    Palm Beach County, Florida, HFA, M/F Housing Revenue Bonds (Indian 
 
    
 
  
    Trace Apartment Project), AMT, Series A, 5.625%, 
 
    
 
  
    1/01/44 (c) 
 
 7,255  
 
 7,053,674 
    Stevens Plantation Community Development District, Florida, Special 
 
    
 
  
    Assessment Revenue Bonds, Series A, 7.10%, 5/01/35 
 
 970  
 
 978,284 
 
 
  
 
    
 
 28,166,361 
Georgia - 4.7%    Atlanta, Georgia, Airport Passenger Facility Charge and Subordinate 
 
    
 
  
    Lien General Revenue Bonds, Series J, 5%, 1/01/34 (c) 
 
 940  
 
 956,309 
    Atlanta, Georgia, Water and Wastewater Revenue Bonds, 
 
    
 
  
    5%, 11/01/37 (c) 
 
 5,000  
 
 5,076,550 
    Main Street Natural Gas, Inc., Georgia, Gas Project Revenue Bonds, 
 
    
 
  
    Series A, 6.375%, 7/15/38 
 
 1,000  
 
 1,022,270 
 
 
  
 
    
 
 7,055,129 
Illinois - 13.4%    Bolingbrook, Illinois, GO, Refunding, Series B, 6.196%, 
 
    
 
  
    1/01/36 (b)(g) 
 
 23,065  
 
 4,286,169 
    Centerpoint Intermodal Center Program Trust, Illinois, Tax Allocation 
 
    
 
  
    Bonds, Class A, 8%, 6/15/23 (h) 
 
 1,150  
 
 1,084,197 
    Chicago, Illinois, GO, Refunding, Series A, 5.50%, 1/01/11 (a)(d) 
 
 4,340  
 
 4,693,319 
    Chicago, Illinois, GO, Refunding, Series A, 5.50%, 1/01/38 (d) 
 
 1,540  
 
 1,608,900 
    Illinois Health Facilities Authority, Revenue Refunding Bonds (Lake 
 
    
 
  
    Forest Hospital), Series A, 5.75%, 7/01/29 
 
 6,000  
 
 6,133,020 

2

BlackRock Municipal Bond Trust   
Schedule of Investments May 31, 2008 (Unaudited) 
(Percentages shown are based on Net Assets) 
   
 
 
 Par  
 
  
State 
 
Municipal Bonds
 
 (000 ) 
 
Value 
   
Illinois State Finance Authority Revenue Bonds (Friendship Village of
 
    
 
  
   
Schaumburg), Series A, 5.625%, 2/15/37
$
420  
$
343,900 
   
Illinois State Finance Authority Revenue Bonds (Monarch Landing, Inc.
 
    
 
  
   
Project), Series A, 7%, 12/01/37
 
 720  
 
 713,786 
   
Illinois State Finance Authority, Student Housing Revenue Bonds (MJH
 
    
 
  
   
Education Assistance IV LLC), Sub-Series B, 5.375%, 6/01/35
 
 425  
 
 127,725 
   
Metropolitan Pier and Exposition Authority, Illinois, Dedicated State
 
    
 
  
   
Tax Revenue Bonds (McCormick Place Expansion), Series A, 6.06%,
 
    
 
  
   
12/15/37
 
 5,000  
 
 1,060,100 
 
 
 
 
    
 
 20,051,116 
Indiana - 1.3%   
AIG SunAmerica, Inc., Bloomington, Indiana, M/F Housing Revenue
 
    
 
  
   
Bonds (Canterbury House Apartments), Pass-Through Certificates of
 
    
 
  
 
 
Beneficial Ownership, AMT, Series 1, 5.90%, 12/01/34
 
 1,910  
 
 1,913,152 
Kansas - 3.4%   
Wichita, Kansas, Airport Authority, Airport Facilities Revenue Bonds
 
    
 
  
 
 
(Cessna Citation Service Center), AMT, Series A, 6.25%, 6/15/32
 
 5,000  
 
 5,021,200 
Maryland - 2.6%   
Frederick County, Maryland, Special Obligation Tax Bonds (Urbana
 
    
 
  
   
Community Development Authority), Series B, 6.25%, 7/01/30
 
 2,955  
 
 2,818,952 
   
Maryland State Health and Higher Educational Facilities Authority,
 
    
 
  
   
Revenue Refunding Bonds (MedStar Health, Inc.), 5.50%, 8/15/33
 
 1,040  
 
 1,040,988 
 
 
 
 
    
 
 3,859,940 
Michigan - 0.7%   
Michigan State Hospital Finance Authority, Revenue Refunding Bonds
 
    
 
  
 
 
(Henry Ford Health System), Series A, 5.25%, 11/15/46
 
 1,065  
 
 1,033,827 
Mississippi - 0.7%   
Mississippi Business Finance Corporation Revenue Bonds (Northrop
 
    
 
  
 
 
Grumman Ship System), 4.55%, 12/01/28
 
 1,205  
 
 1,121,325 
Nebraska - 1.2%   
Omaha Public Power District, Nebraska, Electric System Revenue
 
    
 
  
 
 
Bonds, Series A, 4.75%, 2/01/44
 
 1,760  
 
 1,715,595 
Nevada - 1.8%   
Clark County, Nevada, EDR, Refunding (Alexander Dawson School of
 
    
 
  
   
Nevada Project), 5%, 5/15/29
 
 1,325  
 
 1,308,027 
   
Las Vegas, Nevada, Special Improvement District Number 809
 
    
 
  
   
Revenue Bonds (Summerlin Area), 5.65%, 6/01/23
 
 1,375  
 
 1,277,732 
 
 
 
 
    
 
 2,585,759 
New Jersey - 13.2%   
Middlesex County, New Jersey, Improvement Authority, Subordinate
 
    
 
  
   
Revenue Bonds (Heldrich Center Hotel/Conference Project), Series B,
 
    
 
  
   
6.25%, 1/01/37
 
 915  
 
 784,228 
   
New Jersey EDA, Cigarette Tax Revenue Bonds, 5.50%, 6/15/24
 
 3,710  
 
 3,609,756 
   
New Jersey EDA, Cigarette Tax Revenue Bonds, 5.50%, 6/15/31 (i)
 
 1,500  
 
 1,533,165 
   
New Jersey EDA, EDR, Refunding (Kapkowski Road Landfill
 
    
 
  
   
Reclamation Improvement District Project), 6.50%, 4/01/28
 
 7,500  
 
 7,732,275 
   
New Jersey EDA, First Mortgage Revenue Refunding Bonds (The
 
    
 
  
   
Winchester Gardens at Ward Homestead Project), Series A,
 
    
 
  
   
5.80%, 11/01/31
 
 1,500  
 
 1,481,760 
   
New Jersey EDA, Special Facility Revenue Bonds (Continental Airlines
 
    
 
  
   
Inc. Project), AMT, 7.20%, 11/15/30
 
 3,000  
 
 2,699,790 

3

BlackRock Municipal Bond Trust   
Schedule of Investments May 31, 2008 (Unaudited) 
(Percentages shown are based on Net Assets) 
   
 
 
 Par  
 
  
State   
Municipal Bonds 
 
 (000 ) 
 
Value 
   
New Jersey State Housing and Mortgage Finance Agency, S/F Housing 
 
    
 
  
   
Revenue Bonds, AMT, Series X, 5.375%, 4/01/30 
$
2,000  
$
2,004,940 
   
 
 
    
 
 19,845,914 
New York - 9.9%   
Albany, New York, IDA, Civic Facility Revenue Bonds (New Covenant 
 
    
 
  
   
Charter School Project), Series A, 7%, 5/01/35 
 
 455  
 
 355,514 
   
Hudson Yards Infrastructure Corporation, New York, Revenue Bonds, 
 
    
 
  
   
Series A, 5%, 2/15/47 (g) 
 
 1,000  
 
 977,000 
   
Metropolitan Transportation Authority, New York, Service Contract 
 
    
 
  
   
Revenue Refunding Bonds, Series A, 5%, 7/01/30 (j) 
 
 1,760  
 
 1,790,466 
   
Metropolitan Transportation Authority, New York, Transportation 
 
    
 
  
   
Revenue Refunding Bonds, Series F, 5%, 11/15/35 
 
 1,000  
 
 1,006,160 
   
New York City, New York, City IDA, Special Facility Revenue Bonds 
 
    
 
  
   
(Continental Airlines Inc. Project), AMT, 7.75%, 8/01/31 
 
 6,165  
 
 5,829,501 
   
New York City, New York, City Transitional Finance Authority, 
 
    
 
  
   
Building Aid Revenue Bonds, Series S-1, 5%, 7/15/24 (g) 
 
 1,000  
 
 1,043,360 
   
New York City, New York, GO, Sub-Series F-1, 5%, 9/01/22 (f) 
 
 1,000  
 
 1,031,200 
   
New York Liberty Development Corporation Revenue Bonds (Goldman 
 
    
 
  
   
Sachs Headquarters), 5.25%, 10/01/35 
 
 2,610  
 
 2,718,419 
   
 
 
    
 
 14,751,620 
North Carolina - 1.6%   
Gaston County, North Carolina, Industrial Facilities and Pollution 
 
    
 
  
   
Control Financing Authority, Revenue Bonds (National Gypsum 
 
    
 
  
   
Company Project), AMT, 5.75%, 8/01/35 
 
 2,945  
 
 2,339,390 
Ohio - 0.7%   
Buckeye Tobacco Settlement Financing Authority, Ohio, Tobacco 
 
    
 
  
   
Settlement Asset-Backed Bonds, Series A-2, 6.50%, 6/01/47 
 
 1,125  
 
 1,050,131 
Oklahoma - 2.0%   
Oklahoma State Development Finance Authority, Revenue Refunding 
 
    
 
  
 
Bonds (Saint John Health System), 5%, 2/15/42 
 
 1,355  
 
 1,314,106 
   
Tulsa, Oklahoma, Municipal Airport Trust, Revenue Refunding Bonds, 
 
    
 
  
   
Series A, 7.75%, 6/01/35 
 
 1,725  
 
 1,674,699 
   
 
 
    
 
 2,988,805 
Oregon - 0.4%   
AIG SunAmerica, Inc., Portland, Oregon, M/F Housing Revenue Bonds 
 
    
 
  
   
(Pacific Tower Apartments), Pass-Through Certificates of Beneficial 
 
    
 
  
   
Ownership, AMT, Series 6, 6.05%, 11/01/34 
 
 540  
 
 541,021 
Pennsylvania - 2.6%   
Pennsylvania Economic Development Financing Authority, Exempt 
 
    
 
  
   
Facilities Revenue Bonds (Reliant Energy), AMT, Series A, 
 
    
 
  
   
6.75%, 12/01/36 
 
 3,870  
 
 3,902,198 
South Carolina - 0.8%   
South Carolina Jobs EDA, Hospital Facilities Revenue Refunding Bonds 
 
    
 
  
   
(Palmetto Health Alliance), Series C, 7%, 8/01/13 (a) 
 
 1,000  
 
 1,177,665 

4

BlackRock Municipal Bond Trust   
Schedule of Investments May 31, 2008 (Unaudited) 
(Percentages shown are based on Net Assets) 
   
 
 
 Par  
 
  
State   
Municipal Bonds 
 
 (000 ) 
 
Value 
Texas - 20.5%   
AIG SunAmerica, Inc., Texas, M/F Housing Revenue Bonds 
 
    
 
  
   
(Copperwood Ranch Apartments), Pass-Through Certificates of 
 
    
 
  
   
Beneficial Ownership, AMT, Series 9, 5.95%, 11/01/35 
$
2,520  
$
2,525,040 
   
Dallas-Fort Worth, Texas, International Airport, Joint Revenue Bonds, 
 
    
 
  
   
AMT, Series C, 6.25%, 11/01/28 (d) 
 
 450  
 
 456,466 
   
Harris County-Houston Sports Authority, Texas, Revenue Refunding 
 
    
 
  
   
Bonds, Senior Lien, Series G, 6.121%, 11/15/41 (b)(d) 
 
 11,690  
 
 1,535,481 
   
Lower Colorado River Authority, Texas, Revenue Refunding Bonds, 
 
    
 
  
   
5%, 5/15/13 (a)(d) 
 
 15  
 
 16,295 
   
Lower Colorado River Authority, Texas, Revenue Refunding Bonds, 
 
    
 
  
   
5%, 5/15/31 (d) 
 
 590  
 
 594,620 
   
Montgomery County, Texas, Municipal Utility District Number 46, 
 
    
 
  
   
Waterworks and Sewer System, GO, 4.75%, 3/01/30 (d) 
 
 430  
 
 425,941 
   
SA Energy Acquisition Public Facilities Corporation, Texas, Gas Supply 
 
    
 
  
   
Revenue Bonds, 5.50%, 8/01/23 
 
 1,775  
 
 1,796,744 
   
SA Energy Acquisition Public Facilities Corporation, Texas, Gas Supply 
 
    
 
  
   
Revenue Bonds, 5.50%, 8/01/24 
 
 1,620  
 
 1,640,687 
   
Texas State Turnpike Authority, Central Texas Turnpike System 
 
    
 
  
   
Revenue Bonds, 6.09%, 8/15/35 (b)(j) 
 
 60,000  
 
 11,979,000 
   
Texas State Turnpike Authority, Central Texas Turnpike System 
 
    
 
  
   
Revenue Bonds, First Tier, Series A, 5%, 8/15/42 (j) 
 
 2,115  
 
 2,085,157 
   
Tyler, Texas, Health Facilities Development Corporation, Hospital 
 
    
 
  
   
Revenue Bonds (Mother Frances Hospital Regional Health Care 
 
    
 
  
   
Center), 6%, 7/01/12 (a) 
 
 6,840  
 
 7,603,891 
   
 
 
    
 
 30,659,322 
Washington - 0.8%   
Washington State Health Care Facilities Authority, Revenue Refunding 
 
    
 
  
   
Bonds (Providence Health System), Series A, 
 
    
 
  
   
4.625%, 10/01/34 (g) 
 
 1,325  
 
 1,250,760 
West Virginia - 0.3%   
West Virginia EDA, Lease Revenue Bonds (Correctional, Juvenile and 
 
    
 
  
   
Public Safety Facilities), Series A, 5%, 6/01/29 (d) 
 
 520  
 
 526,448 
Wisconsin - 4.6%   
Wisconsin State Health and Educational Facilities Authority Revenue 
 
    
 
  
 
Bonds (Aurora Health Care, Inc.), 6.40%, 4/15/33 
 
 1,350  
 
 1,388,691 
   
Wisconsin State Health and Educational Facilities Authority, Revenue 
 
    
 
  
   
Refunding Bonds (Wheaton Franciscan Services, Inc.), 
 
    
 
  
   
5.75%, 2/15/12 (a) 
 
 5,000  
 
 5,527,400 
   
 
 
    
 
 6,916,091 
Puerto Rico - 2.4%   
Puerto Rico Commonwealth Aqueduct and Sewer Authority, Senior 
 
    
 
  
   
Lien Revenue Bonds, Series A, 6%, 7/01/38 
 
 1,200  
 
 1,268,760 
   
Puerto Rico Commonwealth Highway and Transportation Authority, 
 
    
 
  
   
Transportation Revenue Refunding Bonds, Series N, 
 
    
 
  
   
5.25%, 7/01/34 (k) 
 
 1,070  
 
 1,159,591 
   
Puerto Rico Commonwealth Highway and Transportation Authority, 
 
    
 
  
   
Transportation Revenue Refunding Bonds, Series N, 
 
    
 
  
   
5.25%, 7/01/36 (k) 
 
 900  
 
 976,716 
   
 
 
    
 
 3,405,067 
   
Total Municipal Bonds (Cost - $205,377,523) - 139.7% 
 
    
 
 208,231,001 

5

BlackRock Municipal Bond Trust   
Schedule of Investments May 31, 2008 (Unaudited) 
(Percentages shown are based on Net Assets) 
   
 
 
 Par  
 
    
State   
Corporate Bonds
 
 (000 ) 
 
Value
 
Multi-State - 7.9%   
Charter Mac Equity Issuer Trust, 7.20%, 10/31/52 (h)
$
10,500  
$
11,784,360  
   
Total Corporate Bonds (Cost - $10,500,000) - 7.9%
 
    
 
 11,784,360  
   
Municipal Bonds Transferred to Tender Option Bond Trusts (l)
 
    
 
    
California - 1.7%   
Sacramento County, California, Airport System Revenue Bonds, AMT,
 
    
 
    
   
Series B, 5.25%, 7/01/39 (c)
 
 2,500  
 
 2,483,173  
Colorado - 3.3%   
Colorado HFA Revenue Bonds, Catholic Health Revenue Bonds, Series
 
    
 
    
   
C-7, 5%, 9/01/36 (c)
 
 3,750  
 
 3,778,275  
   
Colorado HFA Revenue Bonds (RMK Authority Hospital), Series B,
 
    
 
    
   
5.25%, 3/01/36 (c)
 
 1,085  
 
 1,103,530  
   
 
 
    
 
 4,881,805  
Massachusetts - 1.0%   
Massachusetts State Water Resource Authority, GO, Series A, 5%,
 
    
 
    
   
8/01/41
 
 1,450  
 
 1,480,792  
New York - 0.7%   
Port Authority of New York and New Jersey, GO, Consolidated
 
    
 
    
   
Revenue Bonds, 152nd Series, 5.75%, 11/01/30
 
 1,000  
 
 1,065,762  
Ohio - 3.5%   
Montgomery County, Ohio, Revenue Bonds (Catholic Health),
 
    
 
    
   
Series C-1, 5%, 10/01/41 (c)
 
 1,250  
 
 1,265,179  
   
Ohio State Air Quality Development Authority, Revenue Refunding
 
    
 
    
 
Bonds (Pollution Dayton), Series B, 4.80%, 1/01/34 (g)
 
 4,000  
 
 4,011,160  
   
 
 
    
 
 5,276,339  
Washington - 0.6%   
King County, Washington, Sewer Revenue Refunding Bonds, 5%,
 
    
 
    
   
1/01/36
 
 905  
 
 918,912  
   
Total Municipal Bonds Transferred to Tender Option Bond Trusts
 
    
 
    
   
(Cost - $16,096,781) - 10.8%
 
    
 
 16,106,783  
   
Short-Term Securities
 
 Shares  
 
    
   
Merrill Lynch Institutional Tax-Exempt
 
    
 
    
   
Fund, 1.72% (m)(n)
 
 14,500,000  
 
 14,500,000  
   
Total Short-Term Securities
(Cost - $14,500,000) - 9.7%
 
    
 
 14,500,000  
   
Total Investments (Cost - $246,474,304*) - 168.1%
 
    
 
 250,622,144  
   
Liabilities in Excess of Other Assets - (0.7%)
 
    
 
 (982,043 ) 
   
Liability for Trust Certificates, Including Interest
 
    
 
    
   
Expense and Fees Payable - (6.7%)
 
    
 
 (9,971,758 ) 
   
Preferred Shares, at Redemption Value - (60.7%)
 
    
 
 (90,547,751 ) 
   
Net Assets Applicable to Common Shares - 100.0%
 
    
$
149,120,592  

* The cost and unrealized appreciation (depreciation) of investments as of May 31, 2008, as computed for federal income tax purposes, were as follows:
         
  Aggregate cost 
$
236,483,040  
  Gross unrealized appreciation 
$
8,591,642  
  Gross unrealized depreciation 
 
 (4,417,918 ) 
  Net unrealized appreciation 
$
4,173,724  

(a) 
U.S. government securities, held in escrow, are used to pay interest on this security as well as to retire the bond in full at the date indicated, typically at a premium to par. 
   
(b) 
Represents a zero coupon bond; the interest rate shown reflects the effective yield at the time of purchase. 
   
(c) 
FSA Insured. 
   
(d) 
MBIA Insured. 
   
(e) 
ACA Insured. 

6

BlackRock Municipal Bond Trust 
Schedule of Investments May 31, 2008 (Unaudited) 

(f)     
XL Capital Insured.
   
(g)     
FGIC Insured.
   
(h)     
Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration to qualified institutional investors. Unless otherwise indicated, these securities are not considered to be illiquid.
   
(i)     
Radian Insured.
   
(j)     
AMBAC Insured.
   
(k)     
Assured Guaranty Insured.
   
(l)     
Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust acquired residual interest certificates. These securities serve as a collateral in a financing transaction.
   
(m)     
Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:
 
       
  Affiliate 
Net Activity 
Dividend Income 
  Merrill Lynch Institutional Tax-Exempt Fund 
6,900,000 
$113,799 
 
(n) 
Represents the current yield as of report date.     
• 
Forward interest rate swaps outstanding as of May 31, 2008 were as follows:  
 
   Notional  
 
   Amount Unrealized 
 
  
(000)
Appreciation 
 
 Pay a fixed rate of 3.433% and receive a floating rate based on 1-     
 
 week Securities Industry and Financial Markets Association (SIFMA)     
 
 Municipal Swap Index rate     
 
 
 Broker, JPMorgan Chase     
 
 Expires July 2018 
$35,000
$45,780 

7

Item 2 –   Controls and Procedures

2 (a) – The registrant’s principal executive and principal financial officers or persons performing similar function have concluded that the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the “1940 Act”)) are effective as of a date within 90 days of the filing of this report based on the evaluation of these controls and procedures required by Rule 30a-3(b) under the 1940 Act and Rule 13a-15(b) under the Securities Exchange Act of 1934, as amended.
2 (b) – There were no changes in the registrant’s internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act) that occurred during the registrant’s last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 3 – Exhibits

Certifications – Attached hereto

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.

BlackRock Municipal Bond Trust

By:
/s/ Donald C. Burke
  Donald C. Burke
  Chief Executive Officer of
  BlackRock Municipal Bond Trust
   
Date:  July 18, 2008


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:
/s/ Donald C. Burke
  Donald C. Burke
  Chief Executive Officer (principal executive officer) of
  BlackRock Municipal Bond Trust
   
Date:  July 18, 2008


By:
/s/ Neal J. Andrews
  Neal J. Andrews
  Chief Financial Officer (principal financial officer) of
  BlackRock Municipal Bond Trust
   
Date:  July 18, 2008