N-Q

 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: 811-02688

Name of Fund: BlackRock Municipal Bond Fund, Inc.

BlackRock High Yield Municipal Fund

BlackRock National Municipal Fund

BlackRock Short-Term Municipal Fund

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: John M. Perlowski, Chief Executive Officer, BlackRock Municipal Bond Fund, Inc., 55 East 52^nd Street, New York, NY 10055

Registrant’s telephone number, including area code: (800) 441-7762

Date of fiscal year end: 06/30/2014

Date of reporting period: 09/30/2013

Item 1 – Schedule of Investments

Schedule of Investments September 30, 2013 (Unaudited)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama  — 0.8%
Alabama State Docks Department, Refunding RB, 6.00%, 10/01/40	$	710	$	788,206
County of Jefferson Alabama, RB, Limited Obligation School, Series A, 4.75%, 1/01/25		325		311,565
Phenix City IDB, Refunding RB, Meadwestvaco Coated Board Project, Series A, AMT, 4.13%, 5/15/35		1,750		1,314,495
				2,414,266
Alaska  — 1.1%
Northern Tobacco Securitization Corp., Refunding RB, Tobacco Settlement, Asset-Backed, Series A:
4.63%, 6/01/23		1,125		1,060,729
5.00%, 6/01/32		1,500		1,144,890
5.00%, 6/01/46		1,620		1,121,283
				3,326,902
Arizona  — 1.4%
Florence Town, Inc., IDA, ERB, Legacy Traditional School Project, Queen Creek and Casa Grande Campuses, 6.00%, 7/01/43		1,375		1,213,052
Maricopa County IDA Arizona, RB, Arizona Charter Schools Project, Series A, 6.75%, 7/01/29		185		154,619
Phoenix IDA Arizona, ERB:
Eagle College Prep Project, Series A, 5.00%, 7/01/43		1,445		1,222,687
Great Hearts Academies - Veritas Project, 6.40%, 7/01/47		415		397,732
Phoenix IDA Arizona, Refunding RB, America West Airlines, Inc. Project, AMT, 6.30%, 4/01/23		1,000		982,520
University Medical Center Corp. Arizona, RB, 6.25%, 7/01/29		180		193,531
				4,164,141
Arkansas  — 0.3%
Benton County Public Facilities Board, RB, BCCSO Project, Series A, 6.00%, 6/01/40		750		781,245
California  — 9.4%
California Health Facilities Financing Authority, RB:
St. Joseph Health System, Series A, 5.75%, 7/01/39		1,000		1,104,770
Municipal Bonds	Par (000)		Value
California (continued)
California Health Facilities Financing Authority, RB  (concluded):
Sutter Health, Series B, 6.00%, 8/15/42	$	1,000	$	1,145,150
California Health Facilities Financing Authority, Refunding RB, Catholic Healthcare West, Series A, 6.00%, 7/01/39		265		287,724
California HFA, RB, S/F, Home Mortgage, Series I, AMT:
4.60%, 8/01/21		190		188,431
4.70%, 8/01/26		2,500		2,377,275
4.80%, 8/01/36		1,500		1,371,570
California Pollution Control Financing Authority, RB:
Poseidon Resources (Channel Side) LP Desalination Project, AMT, 5.00%, 7/01/37 (a)		775		690,951
Poseidon Resources (Channel Side) LP Desalination Project, AMT, 5.00%, 11/21/45 (a)		3,485		2,904,991
San Diego County Water Authority Desalination Project Pipeline, 5.00%, 11/21/45		920		823,032
California School Finance Authority, RB:
6.65%, 7/01/33		295		293,389
6.90%, 7/01/43		650		643,500
California Statewide Communities Development Authority, RB, Series A:
American Baptist Homes of the West, 5.00%, 10/01/43		1,000		884,300
Sutter Health, 6.00%, 8/15/42		400		453,412
California Statewide Communities Development Authority, Refunding RB:
American Baptist Homes of the West, 6.25%, 10/01/39		2,575		2,655,366
Eskaton Properties, Inc., 5.25%, 11/15/34		905		860,610
City of Chula Vista California, Refunding RB, San Diego Gas & Electric, Series A, 5.88%, 2/15/34		500		556,460
City of Los Angeles Department of Airports, Refunding RB, 5.00%, 5/15/40 (b)		1,680		1,706,409

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 1

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
California (concluded)
City of Roseville California, Special Tax Bonds, Fiddyment Ranch Community Facilities District No. 1, 5.25%, 9/01/36	$	465	$	411,823
City of San Jose California, RB, Convention Center Expansion & Renovation Project, 6.50%, 5/01/42		760		858,823
City of San Jose California Hotel Tax, RB, Convention Center Expansion & Renovation Project, 6.50%, 5/01/36		310		352,017
Lammersville School District Community Facilities District, Special Tax Bonds, District No. 2002, Mountain House, 5.13%, 9/01/35		325		292,386
Poway Unified School District Public Financing Authority, Refunding, Special Tax Bonds:
4.13%, 9/15/36		1,445		1,186,851
Series B, 5.00%, 9/01/42		1,250		1,166,812
Riverside County Transportation Commission, RB, Senior Lien, Series A, 5.75%, 6/01/48		2,115		2,089,091
San Jose Redevelopment Agency, Tax Allocation Bonds, Merged Area Redevelopment Project (NPFGC), 4.90%, 8/01/33		405		360,592
San Marcos County Unified School District, GO, CAB, Election of 2010, Series B, 5.89%, 8/01/51 (c)		4,425		491,839
Successor Agency to the San Francisco City & County Redevelopment Agency, Special Tax Bonds, Community Facilities District No. 6 (Mission Bay South Public Improvements), Series C, CAB, 6.77%, 8/01/43 (c)		3,000		411,540
Temecula Public Financing Authority, Refunding, Special Tax Bonds, Harveston, Sub-Series B, 5.10%, 9/01/36		165		143,121
Tobacco Securitization Authority of Southern California, Refunding RB, Senior Series A1, 5.00%, 6/01/37		2,140		1,608,467
				28,320,702
Municipal Bonds	Par (000)		Value
Colorado  — 1.7%
Central Platte Valley Metropolitan District, GO, Series A, 5.63%, 12/01/38 (b)	$	775	$	772,350
Colorado Educational & Cultural Facilities Authority, RB, Littleton Preparatory Charter School Project:
5.00%, 12/01/33		450		394,862
5.00%, 12/01/42		545		449,036
Denver Convention Center Hotel Authority, Refunding RB, Senior (Syncora), 5.00%, 12/01/30		1,175		1,170,899
Plaza Metropolitan District No. 1 Colorado, Refunding, Tax Allocation Bonds, Public Improvement Fee, Tax Increment, 5.00%, 12/01/40		425		389,474
Regional Transportation District, RB, Denver Transport Partners, 6.00%, 1/15/41		1,000		1,005,150
Tallyn's Reach Metropolitan District No. 3, GO, Refunding, Limited Tax, 5.13%, 11/01/38		1,035		902,572
				5,084,343
Connecticut  — 0.2%
Mohegan Tribe of Indians of Connecticut, Refunding RB, Public Improvement, Priority Distribution, 6.25%, 1/01/31		605		604,982
Delaware  — 0.4%
Delaware State EDA, RB, Exempt Facilities, Indian River Power LLC Project, 5.38%, 10/01/45		1,230		1,154,330
District of Columbia  — 1.9%
District of Columbia, RB, Methodist Home District of Columbia, Series A:
7.38%, 1/01/30		310		303,499
7.50%, 1/01/39		500		482,930
District of Columbia Tobacco Settlement Financing Corp., Refunding RB, Asset-Backed:
6.50%, 5/15/33		1,510		1,574,009
6.75%, 5/15/40		385		388,842
Metropolitan Washington Airports Authority, Refunding RB:
CAB, Second Senior Lien, Series B (AGC), 5.54%, 10/01/30 (c)		3,005		1,186,645
Senior 1st Lien, Series A, 5.00%, 10/01/39		185		186,238

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 2

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
District of Columbia (concluded)
Metropolitan Washington Airports Authority, Refunding RB  (concluded):
Senior 1st Lien, Series A, 5.25%, 10/01/44	$	1,610	$	1,629,819
				5,751,982
Florida  — 8.1%
Boggy Creek Improvement District, Refunding RB, Special Assessment Bonds, 5.13%, 5/01/43		3,035		2,635,442
County of Hillsborough Florida IDA, RB, National Gypsum Co., Series B, AMT, 7.13%, 4/01/30		1,500		1,500,375
Greater Orlando Aviation Authority Florida, Refunding RB, Special Purpose, Jetblue Airways Corp. Project, AMT, 5.00%, 11/15/36		2,000		1,631,140
Greeneway Improvement District, RB, Special Assessment Bonds, 5.13%, 5/01/43		3,335		2,831,682
Highland Meadows Community Development District, Special Assessment Bonds, Series A, 5.50%, 5/01/36 (d)(e)		490		189,336
Hillsborough County IDA, RB, Tampa General Hospital Project, 5.25%, 10/01/41		970		976,955
Jacksonville Economic Development Commission, RB, Gerdau Ameristeel US, Inc., AMT, 5.30%, 5/01/37		3,300		2,964,324
Lakewood Ranch Stewardship District, Refunding, Special Assessment Bonds, Lakewood Center & New Sector Projects, 8.00%, 5/01/40		515		598,801
Martin County IDA, Refunding RB, Indiantown Cogeneration, L.P. Project, AMT, 4.20%, 12/15/25		1,750		1,475,915
Mid-Bay Bridge Authority, RB, Springing Lien, Series A, 7.25%, 10/01/40		1,450		1,586,981
Palm Beach County Health Facilities Authority, RB, Acts Retirement Life Community, 5.50%, 11/15/33		1,500		1,513,965
Santa Rosa Bay Bridge Authority, RB, 6.25%, 7/01/28 (d)(e)		466		191,208
Municipal Bonds	Par (000)		Value
Florida (concluded)
Sarasota County Health Facilities Authority, Refunding RB, Village On The Isle Project, 5.50%, 1/01/27	$	210	$	214,605
Sumter Landing Community Development District Florida, RB, Sub-Series B, 5.70%, 10/01/38		755		617,816
Tolomato Community Development District, Refunding, CAB Special Assessment:
Bonds, Series A-1, 6.65%, 5/01/40		140		136,517
Series A-2, 6.61%, 5/01/39 (f)		40		29,401
Series A-3, 6.61%, 5/01/40 (f)		90		53,921
Series A-4, 6.61%, 5/01/40 (f)		50		22,174
Tolomato Community Development District, Special Assessment Bonds (d)(e):
Series 1, 6.65%, 5/01/40		5		4,849
Series 2, 6.65%, 5/01/40		330		161,720
Series 3, 6.65%, 5/01/40		105		1
Viera East Community Development District, Refunding, Special Assessment Bonds, 5.00%, 5/01/26		640		597,030
Village Community Development District No. 9, Special Assessment Bonds:
7.00%, 5/01/41		1,640		1,806,821
5.50%, 5/01/42		605		601,430
Village Community Development District No. 10, Special Assessment Bonds, 5.13%, 5/01/43		1,855		1,678,794
Watergrass Community Development District, Special Assessment Bonds, Series A, 5.38%, 5/01/39		650		416,117
				24,437,320
Georgia  — 0.8%
County of Clayton Georgia, Tax Allocation Bonds, Ellenwood Project, 7.50%, 7/01/33		240		239,225

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 3

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

 

Municipal Bonds	Par (000)		Value
Georgia (concluded)
County of Clayton Georgia Development Authority, Refunding RB, Delta Air Lines, Inc. Project, Series A, 8.75%, 6/01/29	$	635	$	736,930
County of DeKalb Georgia Hospital Authority, Refunding RB, DeKalb Medical Center, Inc. Project, 6.13%, 9/01/40		1,240		1,248,593
Gainesville & Hall County Development Authority, Refunding RB, Acts Retirement Life Community, Series A-2, 6.63%, 11/15/39		220		234,351
				2,459,099
Guam  — 0.9%
Guam Government Waterworks Authority, Refunding RB, Water & Wastewater System, 6.00%, 7/01/25		735		743,188
Territory of Guam, GO, Series A:
6.00%, 11/15/19		100		103,561
6.75%, 11/15/29		1,650		1,726,247
7.00%, 11/15/39		160		168,587
				2,741,583
Idaho  — 0.1%
Power County Industrial Development Corp., RB, FMC Corp. Project, AMT, 6.45%, 8/01/32		265		265,196
Illinois  — 6.0%
City of Chicago Illinois Waterworks, Refunding RB, 2nd Lien, Water Project, 5.00%, 11/01/42 (b)		8,610		8,570,394
Illinois Finance Authority, RB, Lake Forest College, Series A, 6.00%, 10/01/48		1,700		1,710,557
Illinois Finance Authority, Refunding RB:
Central Dupage Health, Series B, 5.50%, 11/01/39		1,400		1,463,630
Friendship Village of Schaumburg, 7.13%, 2/15/39		1,000		1,035,380
Lutheran Home & Services Obligated Group, 5.63%, 5/15/42		1,605		1,476,921
Roosevelt University Project, 6.50%, 4/01/44		830		877,584
Swedish Covenant, Series A, 6.00%, 8/15/38		1,000		1,062,910
Municipal Bonds		Par (000)		Value
Illinois (concluded)
Metropolitan Pier & Exposition Authority, Refunding RB, CAB, McCormick Place Expansion Project, Series B (AGM), 6.08%, 6/15/44 (c)	$	3,455	$	549,138
Quad Cities Regional EDA, Refunding RB, Augustana College, 4.75%, 10/01/32		925		886,982
Railsplitter Tobacco Settlement Authority, RB, 6.00%, 6/01/28		390		416,352
				18,049,848
Indiana  — 1.7%
City of Carmel, RB, Barrington Carmel Project, Series A:
7.13%, 11/15/42		1,500		1,482,585
7.13%, 11/15/47		1,500		1,470,660
Indiana Finance Authority, RB, Ohio River Bridges East End Crossing Project, Series A, AMT:
5.00%, 7/01/44		370		320,627
5.00%, 7/01/48		1,230		1,046,435
Indiana Finance Authority, Refunding RB, Marquette Project, 5.00%, 3/01/39		725		654,573
Indiana Health Facility Financing Authority, Refunding RB, Methodist Hospital, Inc., 5.38%, 9/15/22		185		185,211
				5,160,091
Iowa  — 2.5%
Iowa Finance Authority, RB, Midwestern Disaster Area, Alcoa, Inc. Project, 4.75%, 8/01/42		2,500		2,073,675
Iowa Finance Authority, Refunding RB:
Development, Care Initiatives Project, Series A, 5.00%, 7/01/19		500		503,280
Midwestern Disaster Area, Iowa Fertilizer Co. Project, 5.50%, 12/01/22		3,295		3,175,292
Sunrise Retirement Community Project, 5.50%, 9/01/37		890		752,326
Sunrise Retirement Community Project, 5.75%, 9/01/43		1,385		1,172,181
				7,676,754

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 4

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Kentucky  — 0.8%
Kentucky Economic Development Finance Authority, RB, Owensboro Medical Health System, Series A:
6.38%, 6/01/40	$	1,050	$	1,110,207
6.50%, 3/01/45		1,000		1,058,530
Kentucky Economic Development Finance Authority, Refunding RB, Norton Healthcare, Inc., Series B (NPFGC), 4.59%, 10/01/24 (c)		250		151,735
				2,320,472
Louisiana  — 1.1%
Louisiana Public Facilities Authority, RB, Belle Chasse Educational Foundation Project, 6.75%, 5/01/41		645		689,886
Tobacco Settlement Financing Corp., Refunding RB, Asset-Backed, Series A, 5.25%, 5/15/35		2,755		2,685,326
				3,375,212
Maine  — 0.4%
Maine Health & Higher Educational Facilities Authority, RB, Maine General Medical Center, 6.75%, 7/01/41		1,075		1,131,072
Maryland  — 2.3%
City of Gaithersburg Maryland, Refunding RB, Asbury Maryland Obligation, Series B, 6.00%, 1/01/23		750		802,650
County of Frederick Maryland, RB, Jefferson Technology Park Project, Series B, 7.13%, 7/01/43		1,910		1,913,361
County of Howard Maryland, Refunding RB, Vantage House Facility, Series A, 5.25%, 4/01/33		500		420,045
Maryland EDC, RB:
Term Project, Series B, 5.75%, 6/01/35		1,500		1,511,670
Transportation Facilities Project, Series A, 5.75%, 6/01/35		265		267,062
Maryland EDC, Refunding RB, CNX Marine Terminals, Inc., 5.75%, 9/01/25		2,000		2,069,600
Municipal Bonds	Par (000)		Value
Maryland (concluded)
Maryland Health & Higher Educational Facilities Authority, RB, Washington Christian Academy, 5.25%, 7/01/18 (d)(e)	$	250	$	75,000
				7,059,388
Massachusetts  — 1.0%
Massachusetts Development Finance Agency, RB:
Foxborough Regional Charter School, Series A, 7.00%, 7/01/42		350		379,036
Linden Ponds, Inc. Facility, Series A-1, 6.25%, 11/15/39		353		283,895
Linden Ponds, Inc. Facility, Series A-2, 5.50%, 11/15/46		19		13,141
Linden Ponds, Inc. Facility, Series B, 0.00%, 11/15/56 (c)		94		523
North Hill Communities Issue, Series A, 6.50%, 11/15/43		1,480		1,399,814
Massachusetts Development Finance Agency, Refunding RB:
Eastern Nazarene College, 5.63%, 4/01/29		500		500,005
Tufts Medical Center, Series I, 6.75%, 1/01/36		510		564,667
				3,141,081
Michigan  — 2.8%
City of Detroit Michigan, GO, Taxable Capital Improvement Limited Tax (d)(e):
Series A-1, 5.00%, 4/01/16		350		139,997
Series A-2, 8.00%, 4/01/14		1,715		685,983
City of Detroit Michigan Sewage Disposal System, Refunding RB, Senior Lien, Series A:
5.00%, 7/01/32		960		866,726
5.25%, 7/01/39		1,660		1,497,619
Kentwood EDC, Refunding RB, Limited Obligation, Holland Home, 5.63%, 11/15/41		1,000		917,010
Michigan State Hospital Finance Authority, Refunding RB, Henry Ford Health, 5.75%, 11/15/39		1,710		1,743,413
Monroe County Hospital Finance Authority, Refunding RB, Mercy Memorial Hospital Corp. Obligation, 5.50%, 6/01/35		1,565		1,568,333

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 5

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Michigan (concluded)
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital, Series V, 8.25%, 9/01/39	$	915	$	1,098,668
				8,517,749
Minnesota  — 0.4%
City of Woodbury Minnesota, Refunding RB, MSA Building Co., Series A, 5.00%, 12/01/43		885		758,941
St. Paul Housing & Redevelopment Authority, RB, Nova Classical Academy, Series A, 6.63%, 9/01/42		500		523,685
				1,282,626
Missouri  — 1.0%
Kansas City Missouri, Tax Allocation Bonds, Kansas City MainCor Project, Series A, 5.25%, 3/01/18 (g)		500		521,570
Kirkwood IDA Missouri, RB, Aberdeen Heights, Series A, 8.25%, 5/15/39		435		482,924
Poplar Bluff Regional Transportation Development District, RB, 4.75%, 12/01/42		2,200		1,932,590
				2,937,084
Nebraska  — 0.4%
Central Plains Energy Project, RB, Gas Project No. 3:
5.25%, 9/01/37		445		444,982
5.00%, 9/01/42		780		745,540
				1,190,522
Nevada  — 0.4%
County of Clark Nevada, RB, Southwest Gas Corp. Project, Series A, AMT (NPFGC), 4.75%, 9/01/36		20		18,802
County of Clark Nevada, Refunding, Special Assessment, Special Improvement District No. 142, Mountain's Edge:
4.00%, 8/01/22		860		793,969
4.00%, 8/01/23		540		492,162
				1,304,933
Municipal Bonds	Par (000)		Value
New Hampshire  — 0.6%
New Hampshire Health & Education Facilities Authority, Refunding RB:
Dartmouth-Hitchcock, 6.00%, 8/01/38	$	435	$	469,987
Southern New Hampshire University, 5.00%, 1/01/34		1,445		1,382,793
				1,852,780
New Jersey  — 3.8%
New Jersey EDA, RB:
Continental Airlines, Inc. Project, AMT, 5.13%, 9/15/23		1,965		1,878,540
Continental Airlines, Inc. Project, AMT, 5.25%, 9/15/29		840		767,794
Kapkowski Road Landfill Project, Series B, AMT, 6.50%, 4/01/31		3,000		3,174,570
Patterson Charter School for Science and Technology, Inc. Project, Series A, 6.10%, 7/01/44		660		662,587
New Jersey Health Care Facilities Financing Authority, Refunding RB:
Barnabas Health, Series A, 5.63%, 7/01/37		1,000		1,019,080
St. Joseph's Healthcare System, 6.63%, 7/01/38		725		726,798
Tobacco Settlement Financing Corp. New Jersey, Refunding RB, Series 1A, 4.50%, 6/01/23		3,385		3,169,748
				11,399,117
New Mexico  — 0.7%
City of Farmington New Mexico, Refunding RB, Arizona Public Service, Series A, 4.70%, 5/01/24		500		519,565
New Mexico Hospital Equipment Loan Council, Refunding RB, Gerald Champion Regional Medical Center Project, 5.50%, 7/01/42		2,030		1,725,399
				2,244,964

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 6

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
New York  — 4.6%
Build NYC Resource Corp., RB, South Bronx Charter School for International Cultures and the Arts Project, Series A, 5.00%, 4/15/43	$	2,750	$	2,263,800
Chautauqua County Industrial Development Agency, RB, NRG Dunkirk Power Project, 5.88%, 4/01/42		1,615		1,633,992
Genesee County Industrial Development Agency, Refunding RB, United Memorial Medical Center Project, 5.00%, 12/01/32		500		451,365
New York City IDA, RB:
American Airlines, Inc., JFK International Airport, AMT, 8.00%, 8/01/28 (i)		235		263,057
British Airways PLC Project, AMT, 7.63%, 12/01/32		1,500		1,511,700
JetBlue Airways Corp. Project, AMT, 5.13%, 5/15/30		1,750		1,494,798
Queens Baseball Stadium, PILOT (AMBAC), 5.00%, 1/01/46		4,000		3,442,080
New York Liberty Development Corp., Refunding RB, 2nd Priority Liberty, Bank of America Tower at One Bryant Park Project, Class 3, 6.38%, 7/15/49		375		397,114
Niagara Area Development Corp., Refunding RB, Solid Waste Disposal Facility, Covanta Energy Project, Series A, AMT, 5.25%, 11/01/42		1,265		1,066,711
Onondaga Civic Development Corp., Refunding RB, St. Joseph's Hospital Health Center Project, 5.00%, 7/01/42		1,220		1,040,440
Yonkers Industrial Development Agency, RB, Sarah Lawrence College Project, Series A, 6.00%, 6/01/41		410		432,263
				13,997,320
North Carolina  — 1.5%
City of Charlotte North Carolina, Refunding RB, Charlotte-Douglas International Airport, Special Facilities Revenue, US Airway, Inc. Project, AMT, 5.60%, 7/01/27		1,180		1,127,596
Municipal Bonds	Par (000)		Value
North Carolina (concluded)
North Carolina Capital Facilities Finance Agency, Refunding RB, High Point University, 4.38%, 5/01/34	$	1,730	$	1,551,862
North Carolina Medical Care Commission, Refunding RB:
Carolina Village Project, 6.00%, 4/01/38		1,000		992,390
First Mortgage, Whitestone Project, Series A, 7.75%, 3/01/41		830		875,775
				4,547,623
Ohio  — 1.1%
Buckeye Tobacco Settlement Financing Authority, RB, Asset-Backed Bonds, Series A-2, 5.75%, 6/01/34		4,460		3,379,966
Oklahoma  — 0.2%
Oklahoma Development Finance Authority, Refunding RB, Inverness Village Community, 6.00%, 1/01/32		695		671,029
Pennsylvania  — 5.1%
Allegheny County IDA, RB, US Steel Corp. Project, AMT, 5.75%, 8/01/42		1,500		1,181,505
Allentown Neighborhood Improvement Zone Development Authority, Refunding RB, Series A:
5.00%, 5/01/35		1,185		1,095,118
5.00%, 5/01/42		2,730		2,440,702
City of Philadelphia Pennsylvania Gas Works, RB, 9th Series, 5.25%, 8/01/40		1,000		978,790
County of Cumberland Pennsylvania Municipal Authority, Refunding RB, Diakon Lutheran, 6.38%, 1/01/39		2,680		2,811,561
East Hempfield Township IDA, Refunding RB, Student Housing Project at Millersville University  of Pennsylvania, 5.00%, 7/01/45		3,200		2,809,280
Lancaster County Pennsylvania Hospital Authority, Refunding RB, Brethren Village Project, Series A, 6.50%, 7/01/40		835		839,016

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 7

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Pennsylvania (concluded)
Lehigh County General Purpose Authority, Refunding RB, Bible Fellowship Church Homes, 5.13%, 7/01/32	$	2,095	$	1,802,936
Pennsylvania Economic Development Financing Authority, RB, US Airways Group, Series A, 7.50%, 5/01/20		1,200		1,298,688
				15,257,596
Puerto Rico  — 0.3%
Puerto Rico Sales Tax Financing Corp., Refunding RB, CAB, First Sub-Series C, 7.65%, 8/01/38 (c)		5,000		774,850
Tennessee  — 0.4%
Tennessee Energy Acquisition Corp., RB, Series A, 5.25%, 9/01/26		1,250		1,316,075
Texas  — 13.6%
Bexar County Health Facilities Development Corp., RB, Army Retirement Residence Project, 6.20%, 7/01/45		1,320		1,379,717
Brazos River Authority, RB, TXU Electric, Series A, AMT, 8.25%, 10/01/30		750		11,243
Central Texas Regional Mobility Authority, Refunding RB:
CAB, 5.83%, 1/01/28 (c)		3,000		1,323,420
CAB, 5.91%, 1/01/29 (c)		500		205,525
CAB, 5.99%, 1/01/30 (c)		1,330		509,350
CAB, 6.06%, 1/01/31 (c)		4,000		1,427,360
Senior Lien, 5.75%, 1/01/25		250		258,720
Senior Lien, 6.25%, 1/01/46		765		780,529
Senior Lien, Series A, 5.00%, 1/01/33		85		79,030
Subordinate Lien, 5.00%, 1/01/33		300		258,921
Subordinate Lien, 5.00%, 1/01/42		265		217,970
City of Houston Texas, RB, Special Facilities Continental Airlines Inc. AMT:
Series A, 6.63%, 7/15/38		1,110		1,095,892
Series E, 6.75%, 7/01/21		630		631,581
Series E, 7.38%, 7/01/22		500		501,255
City of Houston Texas Airport System, Refunding ARB, Senior Lien, Series A, 5.50%, 7/01/39		120		131,326
Municipal Bonds	Par (000)		Value
Texas (continued)
Clifton Higher Education Finance Corp., ERB, Idea Public Schools:
5.50%, 8/15/31	$	255	$	257,415
5.75%, 8/15/41		280		283,514
5.00%, 8/15/42		1,310		1,198,047
Clifton Higher Education Finance Corp., Refunding RB, Uplift Education, Series A, 4.40%, 12/01/47		590		453,492
County of Harris Texas-Houston Sports Authority, Refunding RB, CAB, Senior Lien, Series G (NPFGC), 6.59%, 11/15/41 (c)		350		56,508
Danbury Higher Education Authority, Inc., RB, A.W. Brown Fellowship Charter, Series A (ACA), 5.00%, 8/15/26 (h)		355		397,536
Gulf Coast IDA, RB, Citgo Petroleum Project, AMT, 4.88%, 5/01/25		1,580		1,476,842
Harris County Cultural Education Facilities Finance Corp., Refunding, MRB, Brazos Presbyterian Homes, Inc. Project, Series A:
5.00%, 1/01/38		510		434,086
5.00%, 1/01/43		520		431,631
5.13%, 1/01/48		1,535		1,264,395
Harris County Cultural Education Facilities Finance Corp., Refunding RB, Young Men's Christian Association of the Greater Houston Area, Series A, 5.00%, 6/01/38		2,065		1,936,929
Houston Higher Education Finance Corp., RB, Cosmos Foundation, Inc., Series A:
6.50%, 5/15/31		1,000		1,080,900
6.88%, 5/15/41		205		225,020
Matagorda County Navigation District No. 1, Refunding RB, Central Power & Light Co. Project, Series A, 6.30%, 11/01/29		290		321,445
Matagorda County Navigation District No. 1 Texas, Refunding RB, Series B (AMBAC), AMT, 4.55%, 5/01/30		2,000		1,833,260
New Hope Cultural Education Facilities Corp., RB:
5.88%, 4/01/36		890		862,490
6.00%, 4/01/45		1,355		1,301,410

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 8

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Texas (concluded)
North Texas Education Finance Corp., ERB, Uplift Education, Series A, 5.13%, 12/01/42	$	1,255	$	1,152,868
North Texas Tollway Authority, RB, CAB, Special Project System, Series B, 6.05%, 9/01/37 (c)		725		174,152
North Texas Tollway Authority, Refunding RB, Second Tier System, Series F, 6.13%, 1/01/31		1,150		1,224,290
Red River Health Facilities Development Corp., First MRB Project:
Eden Home, Inc., 7.25%, 12/15/42		1,330		1,274,712
Wichita Falls Retirement Foundation, 5.13%, 1/01/41		600		503,058
Sam Rayburn Municipal Power Agency, Refunding RB, 5.00%, 10/01/21		500		561,690
Tarrant County Cultural Education Facilities Finance Corp., RB, Series A:
CC Young Memorial Home, 8.00%, 2/15/38		330		351,747
Senior Living Center Project, 8.25%, 11/15/44		800		841,312
Tarrant County Cultural Education Facilities Finance Corp., Refunding RB, Northwest Senior Housing, Edgemere Project, Series A, 6.00%, 11/15/36		1,500		1,486,920
Texas Private Activity Bond Surface Transportation Corp., RB, Senior Lien:
LBJ Infrastructure Group LLC, LBJ Freeway Managed Lanes Project, 7.00%, 6/30/40		2,320		2,560,468
NTE Mobility Partners LLC, North Tarrant Express Managed Lanes Project, 6.88%, 12/31/39		1,740		1,892,668
Texas State Turnpike Authority, RB, CAB, (AMBAC) (c):
6.02%, 8/15/30		5,200		1,911,468
6.07%, 8/15/35		10,000		2,702,500
Travis County Health Facilities Development Corp., Refunding RB, 7.13%, 1/01/46		1,920		1,855,757
				41,120,369
Municipal Bonds	Par (000)		Value
Utah  — 1.0%
Utah State Charter School Finance Authority, RB, Navigator Pointe Academy, Series A, 5.63%, 7/15/40	$	1,000	$	948,950
Utah State Charter School Finance Authority, Refunding RB, 6.75%, 10/15/43		2,050		2,089,688
				3,038,638
Virginia  — 5.6%
City of Norfolk Virginia Parking System, Refunding RB, Series B (AMBAC), 5.50%, 2/01/31 (h)		220		220,053
County of Fairfax Virginia EDA, Refunding RB:
Goodwin House, Inc., 5.13%, 10/01/37		1,800		1,804,842
Goodwin House, Inc., 5.13%, 10/01/42		1,185		1,186,908
Vinson Hall LLC, Series A, 5.00%, 12/01/42		970		835,888
Vinson Hall LLC, Series A, 5.00%, 12/01/47		1,265		1,074,833
Hanover County EDA, Refunding RB, Residential Care Facility, Covenant Woods, Series A, 5.00%, 7/01/47		1,015		808,427
Mosaic District Community Development Authority, Special Assessment Bonds, Series A:
6.63%, 3/01/26		515		562,983
6.88%, 3/01/36		450		495,886
Virginia Small Business Financing Authority, RB, Senior Lien AMT:
Elizabeth River Crossings LLC Project, 6.00%, 1/01/37		4,095		4,094,549
Elizabeth River Crossings Project, 5.25%, 1/01/32		420		394,162
Express Lanes LLC, 5.00%, 7/01/34		5,300		4,738,730
Watkins Centre Community Development Authority, RB, 5.40%, 3/01/20		650		631,793
				16,849,054
Washington  — 0.8%
Greater Wenatchee Regional Events Center Public Facilities District, Refunding RB, Series A, 5.50%, 9/01/42		1,005		931,173

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 9

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Washington (concluded)
King County Washington Public Hospital District No. 4, GO, Refunding, Snoqualmie Valley Hospital, 7.00%, 12/01/40	$	545	$	547,948
Washington Health Care Facilities Authority, RB, Kadlec Regional Medical Center, 5.00%, 12/01/42		1,000		859,300
				2,338,421
West Virginia  — 0.5%
City of Princeton West Virginia, Refunding RB, Princeton Community Hospital Project, 5.00%, 5/01/27		1,575		1,575,299
Wisconsin  — 0.5%
Public Finance Authority, Refunding RB, Senior Obligated Group, Series B, AMT, 5.00%, 7/01/42		1,500		1,237,215
Wisconsin Health & Educational Facilities Authority, Refunding RB, St. Johns Communities, Inc., Series A:
7.25%, 9/15/29		75		80,056
7.63%, 9/15/39		145		155,568
				1,472,839
Total Municipal Bonds — 88.2%				266,488,863
Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts (j)
California  — 0.2%
Bay Area Toll Authority, Refunding RB, San Francisco Bay Area, Series F-1, 5.63%, 4/01/44		480		515,087
Colorado  — 1.9%
Colorado Health Facilities Authority, Refunding RB, Sisters of Leavenworth Health System, Series A, 5.00%, 1/01/40		5,595		5,609,435
District of Columbia  — 0.3%
District of Columbia Water & Sewer Authority, Refunding RB, Senior Lien, Series A, 6.00%, 10/01/35 (k)		940		1,048,245
Florida  — 1.2%
County of Miami-Dade Florida, RB, Water & Sewer System, 5.00%, 10/01/34		3,500		3,590,916
Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts (j)	Par (000)		Value
Illinois  — 2.0%
City of Chicago Illinois, GARB, O’Hare International Airport, Third Lien, Series A (NPFGC), 5.00%, 1/01/33 (k)	$	3,495	$	3,426,987
Illinois Finance Authority, RB, The Carle Foundation, Series A (AGC), 6.00%, 8/15/41		2,480		2,646,284
				6,073,271
New York  — 10.4%
Hudson Yards Infrastructure Corp., RB, Series A, 5.75%, 2/15/47 (k)		1,720		1,819,606
New York City Municipal Water Finance Authority, Refunding RB, Water & Sewer System:
2nd General Resolution, Fiscal 2011, Series HH, 5.00%, 6/15/31 (k)		3,015		3,223,020
2nd General Resolution, Fiscal 2013, Series CC, 5.00%, 6/15/47		11,040		11,414,256
2nd General Resolution, Series EE, 5.50%, 6/15/43		3,795		4,059,891
New York Liberty Development Corp., RB, World Trade Center Port Authority, Series 1, 5.25%, 12/15/43		7,725		8,058,985
New York Liberty Development Corp., Refunding RB, 4 World Trade Center Project, 5.75%, 11/15/51 (k)		2,520		2,689,823
				31,265,581
Ohio  — 0.7%
State of Ohio, Refunding RB, Cleveland Clinic Health System Obligated Group, Series A, 5.50%, 1/01/39		2,010		2,180,071
South Carolina  — 0.5%
South Carolina State Housing Finance & Development Authority, MRB, Series B-1, 5.55%, 7/01/39		1,419		1,452,210
Virginia  — 0.8%
Virginia Small Business Financing Authority, Refunding RB, Sentara Healthcare, 5.00%, 11/01/40		2,501		2,525,844
Washington  — 1.0%
City of Bellingham Washington, RB, Water & Sewer, 5.00%, 8/01/40		2,999		3,120,642

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 10

Schedule of Investments (continued)	BlackRock High Yield Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts (j)	Par (000)		Value
Wisconsin  — 0.7%
Wisconsin Health & Educational Facilities Authority, Refunding RB, Froedtert & Community Health, Inc., Series C, 5.25%, 4/01/39 (k)	$	2,179	$	2,234,703
Total Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts — 19.7%				59,616,005
Total Long-Term Investments (Cost — $337,837,650) — 107.9%				326,104,868
Short-Term Securities		Shares
FFI Institutional Tax-Exempt Fund, 0.03% (l)(m)		14,661,168		14,661,168
			Value
Total Short-Term Securities (Cost — $14,661,168) — 4.9%			$	14,661,168
Total Investments (Cost — $352,498,818*) — 112.8%				340,766,036
Liabilities in Excess of Other Assets — (0.9)%				(2,689,873	)
Liability for TOB Trust Certificates, Including Interest Expense and Fees Payable — (11.9%)				(36,029,886	)
Net Assets — 100.0%			$	302,046,277
* As of September 30, 2013, gross unrealized appreciation and gross unrealized depreciation based on cost for federal   income tax purposes were as follows:
Tax cost			$	316,370,117
Gross unrealized appreciation			$	9,320,294
Gross unrealized depreciation				(20,945,956	)
Net unrealized depreciation			$	(11,625,662	)

Notes to Schedule of Investments

(a) Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration to qualified institutional investors.

(b) When-issued security. Unsettled when-issued transactions were as follows:

Counterparty		Value			Unrealized Appreciation/ (Depreciation)
D. A. Davidson & Co.	$		772,350	$		14,260
RBC Capital Markets, LLC			1,706,409			(1,865)
State Street Bank and Trust Co.			8,570,394			90,577

(c) Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.

(d) Non-income producing security.

(e) Issuer filed for bankruptcy and/or is in default of principal and/or interest payments.

(f) Represents a step-up bond that pays an initial coupon rate for the first period and then a higher coupon rate for the following periods. Rate shown is as of report date.

(g) Security is collateralized by Municipal or US Treasury obligations.

(h) US 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.

(i) Variable rate security. Rate shown is as of report date and maturity shown is the date the principal owed can be recovered through demand.

(j) Represent bonds transferred to a TOB. In exchange the Fund acquired residual interest certificates. These bonds serve as collateral in a financing transaction.

(k) All or a portion of security is subject to a recourse agreement, which may require the Fund to pay the liquidity provider in the event there is a shortfall between the TOB trust certificates and proceeds received from the sale of the security contributed to the TOB trust. In the case of a shortfall, the aggregate maximum potential amount the Fund could ultimately be required to pay under the agreements, which expire from January 1, 2015 to November 15, 2019 is $8,633,897.

(l) Represents the current yield as of report date.

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 11

Schedule of Investments (continued) BlackRock High Yield Municipal Fund

(m) Investments in issuers considered to be an affiliate of the Fund during the period ended September 30, 2013, for purposes of Section 2(a)(3) of the 1940 Act, were as follows:

Affiliate	Shares Held at June 30, 2013	Net Activity	Shares Held at September 30, 2013	Income
FFI Institutional Tax-Exempt Fund	2,816,084	11,845,084	14,661,168	$     272

Portfolio Abbreviations

To simplify the listings of portfolio holdings in the Schedule of Investments, the names and descriptions of many of the securities have been abbreviated according to the following list:

ACA	American Capital Access Holding Ltd.
AGC	Assured Guarantee Corp.
AGM	Assured Guaranty Municipal Corp.
AMBAC	American Municipal Bond Assurance Corp.
AMT	Alternative Minimum Tax (subject to)
ARB	Airport Revenue Bonds
CAB	Capital Appreciation Bonds
EDA	Economic Development Authority
EDC	Economic Development Corp.
ERB	Education Revenue Bonds
GARB	General Airport Revenue Bonds
GO	General Obligation Bonds
HFA	Housing Finance Agency
IDA	Industrial Development Authority
IDB	Industrial Development Board
MRB	Mortgage Revenue Bonds
NPFGC	National Public Finance Guarantee Corp.
PILOT	Payment in Lieu of Taxes
RB	Revenue Bonds
S/F	Single-Family
Syncora	Syncora Guarantee

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 12

Schedule of Investments (concluded) BlackRock High Yield Municipal Fund

• Fair Value Measurements - Various inputs are used in determining the fair value of investments. These inputs to valuation techniques are categorized into a disclosure hierarchy consisting of three broad levels for financial reporting purposes as follows:

• Level 1 — unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Fund has the ability to access

• Level 2 — other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)

• Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Fund's own assumptions used in determining the fair value of investments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety.

Changes in valuation techniques may result in transfers into or out of an assigned level within the disclosure hierarchy. In accordance with the Fund's policy, transfers between different levels of the fair value disclosure hierarchy are deemed to have occurred as of the beginning of the reporting period. The categorization of a value determined for investments is based on the pricing transparency of the investment and is not necessarily an indication of the risks associated with investing in those securities. For information about the Fund's policy regarding valuation of investments, please refer to the Fund's most recent financial statements as contained in its annual report.

The following table summarizes the Fund's investments categorized in the disclosure hierarchy as of September 30, 2013:

	Level 1		Level 2		Level 3	Total
Assets:
Investments:
Long-Term Investments1		—	$	326,104,868	—	$	326,104,868
Short-Term Securities	$	14,661,168		—	—		14,661,168
Total	$	14,661,168	$	326,104,868	—	$	340,766,036

¹ See above Schedule of Investments for values in each state or political subdivision.

Certain of the Fund’s liabilities are held at carrying amount, which approximates fair value for financial reporting purposes. As of September 30, 2013, TOB trust certificates of $36,021,581 are categorized as Level 2 within the disclosure hierarchy.

There were no transfers between levels during the period ended September 30, 2013.

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 13

Schedule of Investments September 30, 2013 (Unaudited)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama  — 1.0%
Alabama State Docks Department, Refunding RB, 6.00%, 10/01/40	$	15,945	$	17,701,342
City of Birmingham Alabama Special Care Facilities Financing Authority, RB, Children's Hospital (AGC), 6.00%, 6/01/39		15,835		17,749,452
Courtland IDB Alabama, RB, International Paper Co. Projects, Series A, 6.25%, 11/01/33		2,590		2,752,367
Courtland IDB Alabama, Refunding RB, AMT:
Champion International Corp. Project, 6.00%, 8/01/29		195		195,335
International Paper Co., Series B, 6.25%, 8/01/25		750		750,015
Prattville IDB Alabama, RB, Recovery Zone Facility, Series C, 6.25%, 11/01/33		3,380		3,591,892
				42,740,403
Alaska  — 0.2%
Borough of Matanuska-Susitna Alaska, RB, Goose Creek Correctional Center (AGC):
6.00%, 9/01/28		2,000		2,325,500
6.00%, 9/01/32		5,250		5,966,100
				8,291,600
Arizona  — 0.2%
Maricopa County & Phoenix IDA, Refunding RB, S/F, AMT (Fannie Mae), Series A-2, 5.80%, 7/01/40		405		417,267
Maricopa County IDA Arizona, RB, Arizona Charter Schools Project, Series A, 6.75%, 7/01/29		2,200		1,838,716
Pinal County IDA Arizona, RB, San Manuel Facility Project, AMT, 6.25%, 6/01/26		500		458,790
Vistancia Community Facilities District Arizona, GO:
6.75%, 7/15/22		3,000		3,007,170
5.75%, 7/15/24		2,125		2,182,588
				7,904,531
California  — 20.1%
ABAG Finance Authority for Nonprofit Corps, Refunding RB, Sharp Healthcare, 6.25%, 8/01/39		9,000		9,945,540
Municipal Bonds	Par (000)		Value
California (continued)
Bay Area Toll Authority, RB, San Francisco Bay Area Toll Bridge (a):
Series A-1, 0.97%, 4/01/45	$	75,000	$	74,497,500
Series C-1, 0.97%, 4/01/45		36,000		35,758,800
Bay Area Toll Authority, Refunding RB, San Francisco Bay Area Toll Bridge, Series F-1, 5.00%, 4/01/34 (b)		10,000		10,429,300
California Health Facilities Financing Authority, RB:
Catholic Healthcare West, Series J, 5.63%, 7/01/32		10,000		10,229,200
Sutter Health, Series A, 5.25%, 11/15/46		10,500		10,539,375
Sutter Health, Series B, 6.00%, 8/15/42		21,340		24,437,501
California Health Facilities Financing Authority, Refunding RB:
Catholic Healthcare West, Series A, 6.00%, 7/01/34		5,100		5,174,511
Catholic Healthcare West, Series A, 6.00%, 7/01/39		18,905		20,526,104
Stanford Hospital, Series A-3, 5.50%, 11/15/40		10,645		11,213,975
California State Public Works Board, RB, Various Capital Projects:
Sub-Series A-1, 6.00%, 3/01/35		14,125		15,948,396
Sub-Series I-1, 6.13%, 11/01/29		10,000		11,590,600
Sub-Series I-1, 6.38%, 11/01/34		11,680		13,428,846
California Statewide Communities Development Authority, RB, Series A:
Kaiser Permanente, 5.00%, 4/01/42		60,000		60,082,200
Sutter Health, 6.00%, 8/15/42		10,190		11,550,671
California Statewide Communities Development Authority, Refunding RB, Catholic Healthcare West:
Series B, 5.50%, 7/01/30		2,940		3,185,872
Series E, 5.50%, 7/01/31		1,920		2,057,760
California Statewide Financing Authority, RB, Tobacco Settlement, 6.00%, 5/01/43		5,970		5,438,133

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 1

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
California (continued)
City of Chula Vista California, Refunding RB, San Diego Gas & Electric, Series A, 5.88%, 2/15/34	$	5,850	$	6,510,582
City of San Jose California, RB, Convention Center Expansion & Renovation Project, 6.50%, 5/01/42		5,130		5,797,054
City of San Jose California, Refunding ARB, AMT:
Series A (AMBAC), 5.50%, 3/01/32		6,460		6,869,693
Series A-1, 5.75%, 3/01/34		6,010		6,354,914
Series A-1, 6.25%, 3/01/34		5,250		5,816,895
City of San Jose California Hotel Tax, RB, Convention Center Expansion & Renovation Project, 6.50%, 5/01/36		1,510		1,714,665
County of Orange California Sanitation District, COP, Series B (AGM), 5.00%, 2/01/37		25,000		26,090,750
County of Sacramento California, RB, Subordinated & Passenger Facility Charges/Grant, Series C:
6.00%, 7/01/39		16,945		18,890,117
6.00%, 7/01/41		13,280		14,804,411
Cucamonga Valley Water District, Refunding RB, Series A (AGM), 5.38%, 9/01/35		26,315		28,637,562
Gilroy Public Facilities Financing Authority, Refunding RB, 6.00%, 11/01/33		6,535		7,522,831
Grossmont Healthcare District, GO, Election of 2006, Series B, 6.13%, 7/15/40		3,500		3,951,570
Los Angeles Department of Water & Power, RB:
Power System, Sub-Series A-1 (AGM), 5.00%, 7/01/35		40,000		41,399,200
Series B, 5.00%, 7/01/43		16,000		16,737,440
Los Angeles Department of Water & Power, Refunding RB, Water System, Series A, 5.25%, 7/01/39		40,000		42,548,400
Los Angeles Municipal Improvement Corp., RB, Real Property, Series E:
6.00%, 9/01/34		4,890		5,537,387
6.00%, 9/01/39		9,450		10,647,315
Metropolitan Water District of Southern California, RB, Series A, 5.00%, 7/01/37		10,000		10,603,500
Municipal Bonds	Par (000)		Value
California (concluded)
Modesto Irrigation District, COP, Capital Improvements, Series A, 6.00%, 10/01/39	$	11,755	$	12,772,983
Oakland Unified School District/Alameda County, GO, Election of 2012, 6.63%, 8/01/38		3,750		3,951,863
Orange County Sanitation District, COP, Series A, 5.00%, 2/01/35		10,000		10,623,800
Orange County Water District, COP, Refunding, 5.00%, 8/15/39		15,000		15,622,950
San Francisco City & County Airports Commission, ARB:
2nd Series A, AMT, 5.25%, 5/01/33		2,475		2,573,159
Series E, 6.00%, 5/01/39		24,300		27,599,454
San Francisco City & County Airports Commission, Refunding RB, Second Series 34E, AMT (AGM):
5.75%, 5/01/21		8,220		9,291,559
5.75%, 5/01/23		17,000		19,153,560
San Joaquin County Transportation Authority, Refunding RB, Limited Tax, Measure K, Series A:
6.00%, 3/01/36		12,830		14,641,596
5.50%, 3/01/41		26,390		28,504,367
San Juan Water District, COP, Series A, 6.00%, 2/01/39		10,000		11,220,000
State of California, GO, Various Purposes:
6.50%, 4/01/33		38,500		45,481,205
6.00%, 4/01/38		34,485		39,284,277
Tuolumne Wind Project Authority, RB, Tuolumne Co. Project, Series A, 5.88%, 1/01/29		19,355		21,929,021
University of California, RB, Series O, 5.75%, 5/15/34		1,450		1,635,049
University of California, Refunding RB:
General, Series AI, 5.00%, 5/15/38		10,000		10,538,400
Limited Project, Series G, 5.00%, 5/15/37		20,650		21,727,104
				893,018,917
Colorado  — 0.3%
Central Platte Valley Metropolitan District, GO, Series A, 6.00%, 12/01/38 (b)		1,000		1,038,460

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 2

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Colorado (concluded)
Colorado Health Facilities Authority, RB, Catholic Health Initiatives, Series D, 6.25%, 10/01/33	$	4,385	$	4,971,099
Plaza Metropolitan District No. 1, Tax Allocation Bonds, Public Improvement Fee, Tax Increment, 8.00%, 6/01/14 (c)		7,700		8,173,088
				14,182,647
Delaware  — 0.5%
County of Sussex Delaware, RB, NRG Energy, Inc., Indian River Project, 6.00%, 10/01/40		19,500		19,954,740
District of Columbia  — 1.0%
District of Columbia, RB, Series A, 5.50%, 12/01/30		20,530		22,975,739
District of Columbia Water & Sewer Authority, Refunding RB, Series A:
6.00%, 10/01/35		12,630		14,087,502
5.50%, 10/01/39		7,475		7,981,506
				45,044,747
Florida  — 4.9%
Anthem Park Community Development District, Special Assessment Bonds, 5.80%, 5/01/36 (d)(e)		1,720		1,220,667
City of State Augustine, RB, 5.75%, 10/01/41		1,000		1,081,130
County of Escambia Florida, RB, International Paper Co. Projects, Series B, 6.25%, 11/01/33		7,500		7,970,175
County of Hillsborough Florida IDA, RB, National Gypsum Co., Series B, AMT, 7.13%, 4/01/30		7,750		7,751,937
County of Miami-Dade Florida, GO, Building Better Communities Program:
Series B, 6.38%, 7/01/28		9,300		10,715,739
Series B-1, 5.75%, 7/01/33		2,400		2,649,360
Series B-1, 6.00%, 7/01/38		30,000		33,457,500
County of Miami-Dade Florida, Refunding RB:
Miami International Airport, Series A, AMT (AGC), 5.50%, 10/01/26		7,000		7,789,320
Miami International Airport, Series A, AMT (AGC), 5.50%, 10/01/27		5,495		6,019,278
Water & Sewer Systems, Series C, 6.00%, 10/01/23		25,000		29,346,750
Municipal Bonds	Par (000)		Value
Florida (continued)
Fiddlers Creek Community Development District No. 2, Special Assessment Bonds, Series A, 6.38%, 5/01/35 (d)(e)	$	6,850	$	3,563,781
Florida Housing Finance Corp., Refunding RB, AMT, Homeowner Mortgage, Series 1 (Ginnie Mae), 6.00%, 7/01/39		1,980		2,056,052
Florida Ports Financing Commission, Refunding RB, State Transportation Trust Fund, Series B, AMT, 5.13%, 6/01/27		10,000		10,826,600
Harbor Bay Community Development District Florida, Special Assessment Bonds, Series A, 7.00%, 5/01/33		935		937,206
Highland Meadows Community Development District, Special Assessment Bonds, Series A, 5.50%, 5/01/36 (d)(e)		1,090		421,176
Highlands County Health Facilities Authority, RB, Adventist Health System/Sunbelt, Series B, 6.00%, 11/15/37		4,990		5,618,391
Hillsborough County IDA, RB, National Gypsum Co., AMT, Series A, 7.13%, 4/01/30		6,000		6,014,460
Jacksonville Electric Authority Florida, RB:
Scherer 4 Project, Series A, 6.00%, 10/01/37		11,225		11,458,817
Sub-Series A, 5.63%, 10/01/32		10,525		11,494,037
Sub-Series A, 5.50%, 10/01/39		10,000		10,172,200
Miami-Dade County, RB, Series A, 6.00%, 10/01/38		6,175		6,727,477
Mid-Bay Bridge Authority, RB, Springing Lien, Series A, 7.25%, 10/01/40		14,350		15,705,644
Orange County Health Facilities Authority, RB, 5.00%, 1/01/39		8,685		8,756,130
State of Florida, GO, Board of Education, Series A:
5.38%, 6/01/33		4,000		4,434,480
5.50%, 6/01/38		4,790		5,325,091
State of Florida, RB, Board of Education Lottery Revenue, Series A, 5.75%, 7/01/28		3,890		4,489,527

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 3

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Florida (concluded)
Sterling Hill Community Development District, Refunding RB, Special Assessment Bonds, Series B, 5.50%, 11/01/10 (d)(e)	$	160	$	103,051
Watergrass Community Development District, Special Assessment Bonds, Series B:
5.13%, 11/01/14		1,000		856,790
6.96%, 11/01/17		755		696,767
				217,659,533
Georgia  — 1.9%
City of Atlanta Georgia Department of Aviation, Refunding GARB, Series C, 6.00%, 1/01/30		30,000		34,025,700
County of DeKalb Georgia Hospital Authority, Refunding RB, DeKalb Medical Center, Inc. Project, 6.13%, 9/01/40		2,000		2,013,860
Fulton County Residential Care Facilities for the Elderly Authority, Refunding RB, Canterbury Court Project, Series A, 6.00%, 2/15/22		2,250		2,250,563
Municipal Electric Authority of Georgia, Refunding RB:
Project One, Sub-Series D, 6.00%, 1/01/23		10,000		11,682,600
Series EE (AMBAC), 7.00%, 1/01/25		20,000		26,595,600
Richmond County Development Authority, RB, Recovery Zone Facility, International Paper Co., Series B, 6.25%, 11/01/33		3,625		3,852,251
Rockdale County Development Authority, RB, Visy Paper Project, Series A, AMT, 6.13%, 1/01/34		5,000		5,018,400
				85,438,974
Illinois  — 7.8%
Bolingbrook Special Service Area No. 1, Special Tax Bonds, Forest City Project, 5.90%, 3/01/27		1,000		846,520
Chicago Transit Authority, RB, Federal Transit Administration Section 5309, Series A (AGC), 6.00%, 6/01/26		15,000		16,268,550
City of Chicago Illinois, GARB, O’Hare International Airport Third Lien:
Series B-2, AMT (NPFGC), 6.00%, 1/01/27		17,690		17,865,662
Municipal Bonds	Par (000)		Value
Illinois (continued)
City of Chicago Illinois, GARB, O’Hare International Airport Third Lien  (concluded):
Series B-2, AMT (Syncora), 6.00%, 1/01/29	$	70,000	$	70,660,800
Series C, 6.50%, 1/01/41		24,570		28,284,738
City of Chicago Illinois Board of Education, GO, Series A (AGM), 5.50%, 12/01/39		39,205		39,560,982
City of Chicago Illinois Wastewater Transmission, RB, Series A (BHAC), 5.50%, 1/01/38		3,000		3,231,270
Illinois Finance Authority, RB:
Advocate Health Care Network, Series D, 6.50%, 11/01/38		7,020		7,891,673
Carle Foundation, Series A, 6.00%, 8/15/41		6,450		6,930,332
Carle Foundation, Series A (AGM), 6.00%, 8/15/41		3,675		3,921,409
Community Rehabilitation Providers Facilities, Series A, 6.50%, 7/01/22		810		780,127
DePaul University, Series A, 6.13%, 10/01/40		11,735		12,877,285
Rush University Medical Center Obligation Group, Series B, 7.25%, 11/01/30		5,280		6,202,574
Rush University Medical Center, Series C, 6.38%, 11/01/29		2,860		3,193,876
Rush University Medical Center, Series C, 6.63%, 11/01/39		80		88,894
University of Chicago, Series B, 6.25%, 7/01/38		25,000		27,507,500
Illinois Finance Authority, Refunding RB:
Central Dupage Health, Series B, 5.50%, 11/01/39		4,205		4,396,117
Northwestern Memorial Hospital, Series A, 6.00%, 8/15/39		29,905		33,453,527
Northwestern Memorial Hospital, Series B, 6.00%, 8/15/14 (c)		1,200		1,260,324
OSF Healthcare System, Series A, 7.00%, 11/17/14 (c)		3,335		3,587,560
OSF Healthcare System, Series A, 7.13%, 11/17/14 (c)		1,970		2,121,966
OSF Healthcare System, Series A, 6.00%, 5/15/39		11,100		11,938,827

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 4

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Illinois (concluded)
Illinois Finance Authority, Refunding RB  (concluded):
Roosevelt University Project, 6.50%, 4/01/39	$	8,000	$	8,487,040
Rush University Medical Center Obligation Group, Series A, 7.25%, 11/01/30		6,900		8,105,637
Railsplitter Tobacco Settlement Authority, RB, 6.00%, 6/01/28		13,865		14,801,858
University of Illinois, RB, Series A, 5.75%, 4/01/38		170		186,876
Village of Hodgkins Illinois, RB, Metropolitan Biosolids Management LLC Project, AMT, 6.00%, 11/01/23		10,000		10,005,400
Village of Wheeling Illinois, Tax Allocation Bonds, North Milwaukee/Lake-Cook TIF Project, 6.00%, 1/01/25		1,335		1,280,092
				345,737,416
Indiana  — 2.3%
Indiana Finance Authority, RB, Wastewater Utility, First Lien, CWA Authority Project, Series A, 5.25%, 10/01/38		4,000		4,186,040
Indiana Finance Authority, Refunding RB:
Duke Energy Indiana Project, Series B, 6.00%, 8/01/39		11,000		11,949,520
Parkview Health System, Series A, 5.75%, 5/01/31		1,570		1,660,354
Trinity Health, Series A, 5.63%, 12/01/38		12,000		12,993,960
US Steel Corp. Project, 6.00%, 12/01/26		14,005		13,330,799
Indiana Municipal Power Agency, RB, Series B:
5.75%, 1/01/34		700		706,699
6.00%, 1/01/39		19,620		21,764,858
Indianapolis Local Public Improvement Bond Bank, Refunding RB, Waterworks Project Series A:
5.75%, 1/01/38		12,800		13,546,240
(AGC), 5.50%, 1/01/38		21,900		22,996,314
				103,134,784
Iowa  — 1.4%
Iowa Finance Authority, RB, Series A (AGC), 5.63%, 8/15/37		5,600		5,906,992
Municipal Bonds	Par (000)		Value
Iowa (concluded)
Iowa Finance Authority, Refunding RB, Midwestern Disaster Area, Iowa Fertilizer Co. Project, 5.50%, 12/01/22	$	35,000	$	33,728,450
Iowa Student Loan Liquidity Corp., RB, AMT, Senior Series A-2:
5.40%, 12/01/24		13,580		14,613,031
5.50%, 12/01/25		9,035		9,709,553
				63,958,026
Kansas  — 0.0%
Sedgwick & Shawnee Counties Kansas, RB, AMT (Ginnie Mae), 6.95%, 6/01/29		375		396,060
Kentucky  — 0.5%
Kentucky Economic Development Finance Authority, RB, Owensboro Medical Health System, Series A, 6.38%, 6/01/40		20,850		22,045,539
Louisiana  — 2.0%
Louisiana Local Government Environmental Facilities & Community Development Authority, RB, Westlake Chemical Corp. Project:
6.75%, 11/01/32		7,080		7,415,309
Series A, 6.50%, 8/01/29		11,195		11,995,779
Series A-1, 6.50%, 11/01/35		17,185		18,243,252
New Orleans Aviation Board Louisiana, Refunding GARB, Restructuring, Series A-2 (AGC), 6.00%, 1/01/23		1,370		1,559,005
State of Louisiana Gasoline & Fuels Tax, Refunding RB, Second Lien, Series B (a):
0.60%, 5/01/43		32,000		31,827,200
0.68%, 5/01/43		20,000		19,783,800
				90,824,345
Maine  — 0.4%
Maine Health & Higher Educational Facilities Authority, RB, Maine General Medical Center:
7.50%, 7/01/32		12,365		13,865,987
6.95%, 7/01/41		2,205		2,349,384
				16,215,371

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 5

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Maryland  — 0.2%
Maryland Health & Higher Educational Facilities Authority, RB, University of Maryland Medical System, Series B (NPFGC), 7.00%, 7/01/22	$	3,980	$	4,689,634
Maryland Health & Higher Educational Facilities Authority, Refunding RB, Charlestown Community Project, 6.25%, 1/01/41		6,000		6,294,780
				10,984,414
Massachusetts  — 1.0%
Massachusetts Development Finance Agency, RB, Foxborough Regional Charter School, Series A, 7.00%, 7/01/42		1,375		1,489,070
Massachusetts Development Finance Agency, Refunding RB:
Covanta Energy Project, Series C, AMT, 5.25%, 11/01/42		10,000		8,375,500
Harvard University, Series B-1, 5.00%, 10/15/40		20,000		21,424,200
Massachusetts HFA, RB, Series B, 7.00%, 12/01/38		4,585		4,960,924
Massachusetts Water Pollution Abatement Trust, RB, Series 13, 5.00%, 8/01/37		7,875		8,245,834
				44,495,528
Michigan  — 1.6%
Lansing Board of Water & Light, RB, Series A, 5.50%, 7/01/41		6,485		6,926,888
Michigan State Building Authority, Refunding RB, Facilities Program, Series I:
6.00%, 10/15/38		12,455		13,840,245
6.25%, 10/15/38		7,500		8,471,625
Michigan State HDA, RB, Series C, AMT, 5.50%, 12/01/28		1,535		1,582,339
Michigan State Hospital Finance Authority, Refunding RB, Henry Ford Health, 5.75%, 11/15/39		4,285		4,368,729
Michigan Strategic Fund, Refunding RB, Detroit Edison Co. Project, Series A, AMT, 5.50%, 6/01/30		7,345		7,346,249
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital:
Series V, 8.25%, 9/01/39		18,130		21,769,235
Municipal Bonds	Par (000)		Value
Michigan (concluded)
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital  (concluded):
Series W, 6.00%, 8/01/39	$	5,145	$	5,431,525
				69,736,835
Minnesota  — 0.6%
City of Minneapolis Minnesota, Refunding RB, Fairview Health Services:
Series A, 6.75%, 11/15/32		5,940		6,834,148
Series B (AGC), 6.50%, 11/15/38		17,905		20,464,162
Ramsey County Housing & Redevelopment Authority Minnesota, RB, Hanover Townhouses Project, AMT, 6.00%, 7/01/31		1,110		1,110,943
				28,409,253
Mississippi  — 0.1%
County of Warren Mississippi, RB, International Paper Co. Project, Series A, 6.50%, 9/01/32		1,500		1,596,975
County of Warren Mississippi, Refunding RB, International Paper Co. Project, Series B, AMT, 6.75%, 8/01/21		1,700		1,702,635
				3,299,610
Missouri  — 0.1%
City of Fenton Missouri, Refunding, Tax Allocation Bonds, Gravois Bluffs Redevelopment Project, 5.00%, 4/01/14		1,000		1,018,940
City of Saint Louis Missouri, RB, Lambert-St. Louis International, Series A-1, 6.25%, 7/01/29		1,175		1,305,754
				2,324,694
Nevada  — 2.6%
City of Las Vegas Nevada, GO, Limited Tax, Performing Arts Center, 6.00%, 4/01/34		12,925		14,117,202
City of Reno Nevada, Special Assessment Bonds, Somerset Parkway, 6.63%, 12/01/22		1,485		1,488,222
Clark County Water Reclamation District, GO, Series B:
5.75%, 7/01/34		3,125		3,546,688
5.75%, 7/01/38		32,685		37,021,973

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 6

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Nevada (concluded)
County of Clark Nevada Airport System, ARB, Series B, 5.75%, 7/01/42	$	51,700	$	57,237,587
				113,411,672
New Hampshire  — 0.4%
New Hampshire Health & Education Facilities Authority, Refunding RB, Dartmouth-Hitchcock, 6.00%, 8/01/38		15,500		16,746,665
New Jersey  — 6.5%
Cape May County Industrial Pollution Control Financing Authority, Refunding RB, Atlantic City Electric Co., Series A (NPFGC), 6.80%, 3/01/21		5,000		6,119,300
Monmouth County Improvement Authority, RB, Brookdale Community College Project, 6.00%, 8/01/38		3,600		4,079,340
New Jersey EDA, RB:
Motor Vehicle Surcharge, Series A (NPFGC), 5.25%, 7/01/33		26,500		27,073,195
Rutgers University, College Avenue Redevelopment Project, 5.00%, 6/15/38		6,880		7,208,382
New Jersey EDA, Refunding RB, New Jersey American Water Co., Inc. Project, Series B, AMT, 5.60%, 11/01/34		8,270		8,744,615
New Jersey Educational Facilities Authority, Refunding RB, University of Medicine & Dentistry, Series B (c):
7.13%, 6/01/19		2,870		3,707,810
7.50%, 6/01/19		9,200		12,071,320
New Jersey Health Care Facilities Financing Authority, Refunding RB, AHS Hospital Corp.:
6.00%, 7/01/37		1,200		1,333,200
6.00%, 7/01/41		30,685		34,651,957
New Jersey Higher Education Student Assistance Authority, Refunding RB, Series 1, AMT:
5.50%, 12/01/25		950		1,002,307
5.75%, 12/01/27		500		534,250
5.75%, 12/01/28		450		476,708
New Jersey State Housing & Mortgage Finance Agency, RB, S/F Housing, Series AA:
6.38%, 10/01/28		1,230		1,290,332
6.50%, 10/01/38		1,480		1,511,909
Municipal Bonds	Par (000)		Value
New Jersey (concluded)
New Jersey State Turnpike Authority, Refunding RB (a):
Series D, 0.60%, 1/01/22	$	17,000	$	16,952,740
Series D, 0.69%, 1/01/23		17,000		16,890,180
Series D, 0.75%, 1/01/24		15,000		14,856,450
Series E, 0.60%, 1/01/22		12,000		11,966,640
Series E, 0.69%, 1/01/23		10,000		9,935,400
Series E, 0.75%, 1/01/24		10,000		9,904,300
New Jersey Transportation Trust Fund Authority, RB, Transportation System:
Series A, 5.13%, 6/15/28		5,000		5,338,900
Series A, 5.13%, 6/15/29		12,875		13,625,484
Series A, 5.88%, 12/15/38		4,255		4,739,006
Series AA, 5.00%, 6/15/38		37,500		38,293,875
Series AA, 5.50%, 6/15/39		11,400		12,149,322
Series B, 5.25%, 6/15/36		24,600		25,788,918
				290,245,840
New Mexico  — 0.0%
County of Santa Fe New Mexico, RB, (AGM), 6.00%, 2/01/27		250		292,625
New Mexico Mortgage Finance Authority, RB, S/F Mortgage Program, Series D, AMT (Fannie Mae), 6.15%, 7/01/35		1,000		1,062,120
				1,354,745
New York  — 5.5%
City of New York New York, GO:
Series D-1, 5.00%, 8/01/30 (b)		9,000		9,733,050
Series E-1, 6.25%, 10/15/28		10,100		11,800,032
Long Island Power Authority, Refunding RB, Electric System, Series A, 6.00%, 5/01/33		49,450		55,928,939
Metropolitan Transportation Authority, RB:
Series C, 6.50%, 11/15/28		21,870		25,582,214
Series D, 5.25%, 11/15/41		13,925		14,332,306
New York City Housing Development Corp., RB, Series M:
6.50%, 11/01/28		4,300		4,646,322
6.88%, 11/01/38		7,785		8,371,522
New York State Dormitory Authority, ERB, Series B, 5.75%, 3/15/36		17,250		19,290,157
New York State Dormitory Authority, RB, Columbia University, 5.00%, 10/01/41		39,000		41,350,530

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 7

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
New York (concluded)
New York State Thruway Authority, Refunding RB, General, Series G (AGM), 5.00%, 1/01/32	$	5,000	$	5,194,550
Port Authority of New York & New Jersey, Refunding ARB, Consolidated, 152nd Series, AMT, 5.75%, 11/01/30		4,695		5,019,753
Sales Tax Asset Receivable Corp., Refunding RB, Series A, (AMBAC):
5.25%, 10/15/27		13,935		14,548,976
5.00%, 10/15/32		22,500		23,270,400
Triborough Bridge & Tunnel Authority, RB, General, Series A-2, 5.38%, 11/15/38		5,715		5,970,518
				245,039,269
North Carolina  — 0.2%
Columbus County Industrial Facilities & Pollution Control Financing Authority North Carolina, RB, International Paper Co. Projects, Series B, 6.25%, 11/01/33		3,000		3,188,070
Durnham Capital Finance Corp., Refunding RB, 5.00%, 6/01/32		3,710		4,011,067
				7,199,137
Ohio  — 1.0%
County of Lucas Ohio, Refunding RB, Promedica Healthcare, Series A:
5.75%, 11/15/31		500		551,410
6.50%, 11/15/37		12,140		13,927,615
6.00%, 11/15/41		2,400		2,652,912
County of Montgomery Ohio, Refunding RB, Catholic Health, Series A, 5.50%, 5/01/34		10,500		11,439,540
State of Ohio, Refunding RB, Cleveland Clinic Health, Series A, 5.50%, 1/01/39		5,430		5,890,355
State of Ohio Turnpike Commission, RB, Junior Lien, Series A, 5.25%, 2/15/39		7,600		7,942,912
				42,404,744
Oklahoma  — 0.1%
Oklahoma County Finance Authority, Refunding RB, Epworth Villa Project, Series A, 5.13%, 4/01/42		6,300		5,815,782
Municipal Bonds	Par (000)		Value
Oregon  — 0.0%
City of Portland Oregon, M/F HRB, Lovejoy Station Apartments Project, AMT (NPFGC), 5.90%, 7/01/23	$	425	$	425,735
Pennsylvania  — 1.6%
Allegheny County IDA, Refunding RB, Environmental Improvement, US Steel Corp. Project:
6.75%, 11/01/24		5,785		6,009,053
6.75%, 12/01/27		5,000		5,052,450
6.88%, 5/01/30		5,000		5,100,150
City of Philadelphia Pennsylvania Gas Works, RB, 12th Series B (NPFGC), 7.00%, 5/15/20 (f)		3,515		4,215,399
County of Cumberland Pennsylvania Municipal Authority, Refunding RB, Diakon Lutheran:
6.38%, 1/01/39		10,575		11,094,127
6.50%, 1/01/39		2,245		2,251,308
Dauphin County General Authority, Refunding RB, Pinnacle Health System Project, Series A:
6.00%, 6/01/29		12,530		13,466,868
6.00%, 6/01/36		2,970		3,150,873
Lancaster County Hospital Authority, Refunding RB, Brethren Village Project, Series A, 6.25%, 7/01/26		1,160		1,178,421
Pennsylvania Economic Development Financing Authority, RB:
Allegheny Energy Supply Co., 7.00%, 7/15/39		12,000		12,245,400
American Water Co. Project, 6.20%, 4/01/39		3,475		3,774,927
Pennsylvania Turnpike Commission, RB, Subordinate, Special Motor License Fund, 6.00%, 12/01/36		950		1,066,727
Philadelphia IDA, RB, Commercial Development, AMT, 7.75%, 12/01/17		1,265		1,265,708
				69,871,411
South Carolina  — 0.2%
County of Richland South Carolina, Refunding RB, International Paper Co. Project, AMT, 6.10%, 4/01/23		3,000		3,002,640

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 8

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
South Carolina (concluded)
South Carolina Jobs-EDA, Refunding RB, Palmetto Health, Series A, (AGM):
6.25%, 8/01/34	$	1,315	$	1,441,805
6.50%, 8/01/39		2,955		3,271,510
South Carolina State Public Service Authority, Refunding RB, Santee Cooper, Series A, 5.50%, 1/01/38		2,390		2,523,386
				10,239,341
Tennessee  — 1.3%
County of Rutherford Tennessee Health & Educational Facilities Board, RB, Ascension Health, Series C, 5.00%, 11/15/47		23,740		23,912,115
Metropolitan Government of Nashville & Davidson County Tennessee, Refunding RB, Water and Sewer, 5.00%, 7/01/40		33,240		34,859,453
				58,771,568
Texas  — 7.2%
City of Dallas Texas Waterworks & Sewer System, Refunding RB, Series A, 5.00%, 10/01/41		16,855		17,753,709
City of Houston Texas Utility System, Refunding RB, Combined First Lien, Series A (AGC), 6.00%, 11/15/35		32,350		36,713,368
Dallas Area Rapid Transit, Refunding RB, Senior Lien, 5.00%, 12/01/42		20,000		20,973,200
Dallas/Fort Worth International Airport, Refunding RB, Series G, 5.00%, 11/01/29		5,155		5,328,672
Harris County Flood Control District, GO, Refunding Series A, 5.00%, 10/01/31		9,100		9,760,296
Matagorda County Navigation District No. 1, Refunding RB, Central Power & Light Co. Project, Series A, 6.30%, 11/01/29		9,775		10,834,903
North Texas Toll way Authority, RB, Special Projects System, Series A, 6.00%, 9/01/41		4,815		5,352,450
North Texas Toll way Authority, Refunding RB:
First Tier System, 6.00%, 1/01/34		11,490		12,354,278
First Tier System (NPFGC), Series B, 5.75%, 1/01/40		9,870		10,597,419
Municipal Bonds	Par (000)		Value
Texas (concluded)
North Texas Tollway Authority, Refunding RB  (concluded):
First Tier System, Series A (NPFGC), 5.75%, 1/01/40	$	7,720	$	8,288,964
First Tier System, Series K-2 (AGC), 6.00%, 1/01/38		2,245		2,467,682
First Tier, Series A, 6.00%, 1/01/28		1,000		1,128,660
Second Tier System, Series F, 6.13%, 1/01/31		25,615		27,269,729
Port of Bay City Authority Texas, RB, Hoechst Celanese Corp. Project, AMT, 6.50%, 5/01/26		4,000		4,001,320
State of Texas, GO:
Transportation Commission, Highway Improvement, 5.00%, 4/01/42		20,000		21,178,200
Refunding Water Financial Assistance, 5.75%, 8/01/22		3,445		3,460,571
Tarrant County Cultural Education Facilities Finance Corp., RB, Scott & White Healthcare, 6.00%, 8/15/45		50,000		56,531,500
Tarrant County Cultural Education Facilities Finance Corp., Refunding RB, Northwest Senior Housing, Edgemere Project, Series A, 6.00%, 11/15/26		2,200		2,212,232
Texas Private Activity Bond Surface Transportation Corp., RB, Senior Lien:
LBJ Infrastructure Group LLC, LBJ Freeway Managed Lanes Project, 7.00%, 6/30/40		25,520		28,165,148
NTE Mobility Partners LLC, North Tarrant Express Managed Lanes Project, 6.88%, 12/31/39		23,000		25,018,020
University of Texas System, Refunding RB, Series B, 5.00%, 8/15/35		8,370		8,957,490
				318,347,811
Utah  — 1.9%
City of Salt Lake City Utah, Refunding RB, IHC Hospital, Inc., Series A, 8.13%, 5/15/15 (f)		20		21,379
County of Utah Utah, RB, IHC Health Services, Inc., 5.00%, 5/15/43		57,565		59,252,806
Utah Transit Authority, RB, Series A, 5.00%, 6/15/36		13,000		13,651,820

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 9

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Utah (concluded)
Utah Transit Authority, Refunding RB, 5.00%, 6/15/42	$	10,000	$	10,226,000
				83,152,005
Virginia  — 1.5%
Hampton Redevelopment & Housing Authority, RB, M/F Housing Facility, Tidewater Seniors Apartments Project, AMT, 5.45%, 1/01/34		1,905		1,935,594
Virginia HDA, RB, Rental Housing, Series A, 5.25%, 5/01/41		2,865		2,913,992
Virginia Small Business Financing Authority, RB, Senior Lien, Elizabeth River Crossings LLC Project, AMT, 6.00%, 1/01/37		28,085		28,081,911
Winchester IDA, Refunding RB, Valley Health (BHAC) (AMBAC), 5.25%, 1/01/37		31,970		34,156,428
				67,087,925
Washington  — 2.5%
City of Seattle Washington Housing Authority, RB:
Newholly Project, AMT, 6.25%, 12/01/35		2,750		2,507,643
Replacement Housing Projects, S/F & M/F Housing, 6.13%, 12/01/32		4,150		4,164,981
Port of Seattle, Refunding RB, Intermediate Lien, Series A:
5.00%, 8/01/31		10,000		10,502,000
5.00%, 8/01/33		2,500		2,604,975
State of Washington, GO, Series D, 5.00%, 1/01/33		10,000		10,732,500
University of Washington, Refunding RB, Series A, 5.00%, 7/01/41		44,800		46,931,136
Washington Health Care Facilities Authority, RB:
MultiCare Health System, Series B (AGC), 6.00%, 8/15/39		2,000		2,137,700
Swedish Health Services, Series A, 6.75%, 05/15/21 (c)		16,000		21,054,560
Washington Health Care Facilities Authority, Refunding RB, Catholic Health Initiatives, Series D, 6.38%, 10/01/36		10,000		11,393,800
				112,029,295
Municipal Bonds	Par (000)		Value
Wisconsin  — 1.7%
City of Superior Wisconsin, Refunding RB, Midwest Energy Resources, Series E (NPFCG), 6.90%, 8/01/21	$	7,000	$	8,760,500
Wisconsin Health & Educational Facilities Authority, RB, Ascension Health Alliance, Series D, 5.00%, 11/15/41		45,000		45,236,250
Wisconsin Health & Educational Facilities Authority, Refunding RB, Froedtert Health, Inc., Series A, 5.00%, 4/01/42		20,000		20,000,000
				73,996,750
Total Municipal Bonds — 82.3%				3,651,937,662
Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts (g)
Arizona  — 4.6%
City of Mesa Arizona, RB, Utility System, 5.00%, 7/01/35		30,000		31,430,700
Salt River Project Agricultural Improvement & Power District, RB, Electric System, Series A:
5.00%, 1/01/37		98,935		102,527,600
5.00%, 1/01/38		54,015		56,022,359
Salt River Project Agricultural Improvement & Power District, Refunding RB, Series A, 5.00%, 1/01/35		13,700		14,210,188
				204,190,847
Arkansas  — 0.5%
University of Arkansas, RB, Various Facilities, UAMS Campus (NPFGC), 5.00%, 3/01/36		21,290		22,476,066
California  — 4.4%
Anaheim Public Financing Authority, RB, Distribution System, Second Lien (BHAC), 5.00%, 10/01/34		10,995		11,181,665
County of Orange California, ARB, Series B, 5.25%, 7/01/34		13,045		13,916,605
Los Angeles Department of Water & Power, RB, Power System, Sub-Series A-1 (AMBAC), 5.00%, 7/01/37		27,500		28,630,800
Metropolitan Water District of Southern California, RB, Series A:
5.00%, 1/01/39		10,000		10,546,900
(AGM), 5.00%, 7/01/30		6,827		7,168,776

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 10

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts (g)	Par (000)		Value
California (concluded)
Metropolitan Water District of Southern California, Refunding RB:
Series B, 5.00%, 7/01/35	$	13,168	$	13,828,123
Series C, 5.00%, 7/01/35		13,375		14,066,876
San Diego Community College District California, GO, Election of 2006 (AGM), 5.00%, 8/01/32		18,000		19,444,500
San Diego County Water Authority, COP, Refunding, Series A (AGM), 5.00%, 5/01/33		4,500		4,694,940
San Diego Public Facilities Financing Authority, Refunding RB, Series B, 5.38%, 8/01/34		15,000		16,293,000
San Francisco City & County Public Utilities Commission, Refunding RB, Series A, 5.13%, 11/01/39		23,000		24,338,600
Sequoia Union High School District California, GO, Refunding, Election of 2004, Series B (AGM), 5.50%, 7/01/35		10,055		10,761,716
University of California, RB, General, Series O, 5.25%, 5/15/39		20,695		21,963,590
				196,836,091
Colorado  — 0.0%
Colorado Health Facilities Authority, Refunding RB, Catholic Health Initiatives, Series A, 5.50%, 7/01/34 (h)		1,580		1,717,214
Florida  — 3.9%
City of Tallahassee Florida, RB, Energy System (NPFGC), 5.00%, 10/01/37		10,000		10,097,900
County of Orange Florida School Board, COP, Series A (NPFGC), 5.00%, 8/01/30		2,000		2,088,140
Florida State Turnpike Authority, RB, Department of Transportation, Series B, 5.00%, 7/01/40		35,720		38,247,547
Jacksonville Electric Authority Florida, RB, Sub-Series A, 5.63%, 10/01/32		6,300		6,880,293
State of Florida, GO, Board of Education:
Capital Outlay, Series E, 5.00%, 6/01/37		39,730		43,221,075
Series C, 5.00%, 6/01/37		65,545		70,183,959
				170,718,914
Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts (g)	Par (000)		Value
Illinois  — 0.5%
City of Chicago Illinois, Refunding RB, Waterworks, Second Lien (AGM), 5.25%, 11/01/33	$	5,000	$	5,127,450
Illinois Finance Authority, RB, The Carle Foundation, Series A (AGC), 6.00%, 8/15/41		15,600		16,645,980
				21,773,430
Indiana  — 2.3%
Indiana Finance Authority, RB, Sisters of St. Francis Health, 5.25%, 11/01/39		31,460		31,784,667
Indianapolis Local Public Improvement Bond Bank, RB, PILOT, Infrastructure Project, Series F (AGM):
5.00%, 1/01/35		23,550		24,960,410
5.00%, 1/01/40		7,000		7,343,980
Indianapolis Local Public Improvement Bond Bank, Refunding RB, Waterworks Project, Series A (AGC), 5.50%, 1/01/38		34,125		35,833,206
				99,922,263
Louisiana  — 0.3%
State of Louisiana, RB, Series A (AGM), 5.00%, 5/01/31		11,950		12,580,840
Massachusetts  — 0.7%
Massachusetts School Building Authority, RB:
Senior Dedicated Sales Tax, Series B, 5.00%, 10/15/41		20,000		20,915,200
Series A (AMBAC), 5.00%, 8/15/37		10,000		10,368,700
				31,283,900
Nebraska  — 0.2%
Omaha Public Power District, RB, Series A, 5.00%, 2/01/43		10,000		10,280,400
New York  — 0.1%
New York State Dormitory Authority, ERB, Series B, 5.75%, 3/15/36		2,010		2,247,723
Ohio  — 0.5%
County of Hamilton Ohio, Refunding RB, Sub-Series A (AGM), 5.00%, 12/01/32		20,000		20,751,400

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 11

Schedule of Investments (continued)	BlackRock National Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts (g)	Par (000)		Value
Ohio (concluded)
State of Ohio, RB, Cleveland Clinic Health Obligated Group, Series B, 5.50%, 1/01/34	$	1,000	$	1,062,580
				21,813,980
Texas  — 3.1%
City of Houston Texas, Refunding RB, Combined First Lien:
Series A (AGC), 5.38%, 11/15/38		26,160		27,859,615
Series A (NPFGC), 5.13%, 5/15/28		20,000		20,464,000
City of San Antonio Texas, Refunding RB, Electric and Gas Revenue:
5.00%, 2/01/17 (c)		218		232,269
5.00%, 2/01/32		28,772		30,606,713
Cypress-Fairbanks ISD, GO, Refunding, Schoolhouse (PSF-GTD), 5.00%, 2/15/32		10,000		10,720,200
Dallas Area Rapid Transit, Refunding RB, Senior Lien (AMBAC), 5.00%, 12/01/36		27,860		29,683,390
Harris County Cultural Education Facilities Finance Corp., RB, Texas Children's Hospital Project, 5.50%, 10/01/39		8,500		9,271,630
Harris County Flood Control District, Refunding RB, Contract Tax, Series A, 5.00%, 10/01/39		10,000		10,587,300
				139,425,117
Utah  — 0.7%
County of Utah, RB, IHC Health Services Inc., 5.00%, 5/15/43		30,000		30,879,600
Washington  — 0.6%
Central Puget Sound Regional Transit Authority, RB, Series A:
5.00%, 11/01/34		8,500		8,908,425
5.00%, 11/01/36		15,715		16,283,979
				25,192,404
Total Municipal Bonds Transferred to Tender Option Bond (TOB) Trusts — 22.4%				991,338,789
US Government Sponsored Agency Securities  — 0.0%
Mortgage-Backed Securities  — 0.0%
Ginnie Mae Mortgage-Backed Securities, 6.00%, 11/15/31		—(i)		190
Investment Companies — 0.1%	Shares		Value
iShares S&P National Municipal Bond Fund (j)		46,296	$	4,837,469
Total Long-Term Investments (Cost — $4,487,129,586) — 104.8%				4,648,114,110
Short-Term Securities	Par (000)
Florida  — 2.5%
Broward County Florida School Board, COP, VDRN, Series D (JPMorgan Chase Bank SBPA), 0.40%, 10/07/13 (l)	$	111,975		111,975,000
Tennessee  — 1.5%
Shelby County Health Educational & Housing Facilities Board, Refunding RB, VRDN Methodist Le Bonheur Healthcare (US Bank NA SBPA) (l):
Series A, 0.18%, 10/07/13		14,600		14,600,000
Series B, 0.18%, 10/07/13		50,000		50,000,000
				64,600,000
	Shares
Money Market — 0.8%
FFI Institutional Tax-Exempt Fund, 0.03% (j)(k)		35,341,649		35,341,649
Total Short-Term Securities (Cost — $211,916,649) — 4.8%				211,916,649
Total Investments (Cost — $4,699,046,235*) — 109.6%				4,860,030,759
Other Assets Less Liabilities — 1.0%				46,442,765
Liability for TOB Trust Certificates, Including Interest Expense and Fees Payable — (10.6%)				(471,608,944	)
Net Assets — 100.0%			$	4,434,864,580
* As of September 30, 2013, gross unrealized appreciation and gross unrealized depreciation based on cost for   federal income tax purposes were as follows:
Tax cost			$	4,228,159,031
Gross unrealized appreciation			$	215,028,054
Gross unrealized depreciation				(54,650,810	)
Net unrealized appreciation			$	160,377,244

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 12

Schedule of Investments (continued) BlackRock National Municipal Fund

Notes to Schedule of Investments

(a) Variable rate security. Rate shown is as of report date.

(b) When-issued security. Unsettled when-issued transactions were as follows:

Counterparty		Value		Unrealized Appreciation
D. A. Davidson & Co.	$	1,038,460	$	11,770
RBC Capital Markets, LLC	$	10,429,300	$	21,200
Siebert Brandford Shank & Co.	$	9,733,050	$	2,790

(c) US 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.

(d) Issuer filed for bankruptcy and/or is in default of principal and/or interest payments.

(e) Non-income producing security.

(f) Security is collateralized by municipal or US Treasury obligations.

(g) Represent bonds transferred to a TOB. In exchange the Fund acquired residual interest certificates. These bonds serve as collateral in a financing transaction.

(h) All or a portion of security is subject to a recourse agreement, which may require the Fund to pay the liquidity provider in the event there is a shortfall between the TOB trust certificates and proceeds received from the sale of the security contributed to the TOB trust. In the case of a shortfall, the aggregate maximum potential amount the Fund could ultimately be required to pay under the agreements, which expire July 1, 2017 is $834,226.

(i) Amount is less than $500.

(j) Investments in issuers considered to be an affiliate of the Fund during the period ended September 30, 2013, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliate	Shares Held at June 30, 2013	Net Activity	Shares Held at September 30, 2013		Value at September 30, 2013		Income
FFI Institutional Tax-Exempt Fund	109,118,875	(73,777,226)	35,341,649	$	35,341,649	$	173,553
iShares S&P National Municipal Bond Fund	46,296	—	46,296		4,837,469		—

(k) Represents the current yield as of report date.

(l) Variable rate security. Rate shown is as of report date and maturity shown is the date the principal owed can be recovered through demand.

Portfolio Abbreviations

To simplify the listings of portfolio holdings in the Schedule of Investments, the names and descriptions of many of the securities have been abbreviated according to the following list:

AGC	Assured Guarantee Corp.
AGM	Assured Guaranty Municipal Corp.
AMBAC	American Municipal Bond Assurance Corp.
AMT	Alternative Minimum Tax (subject to)
ARB	Airport Revenue Bonds
BHAC	Berkshire Hathaway Assurance Corp.
COP	Certificates of Participation
COP	Certificates of Participation
EDA	Economic Development Authority
ERB	Education Revenue Bonds

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 13

Schedule of Investments (continued) BlackRock National Municipal Fund

Portfolio Abbreviations

Fannie Mae	Federal National Mortgage Association
GARB	General Airport Revenue Bonds
Ginnie Mae	Government Natioanl Mortgage Association
GO	General Obligation Bonds
HDA	Housing Development Authority
HFA	Housing Finance Agency
HRB	Housing Revenue Bonds
IDA	Industrial Development Authority
IDB	Industrial Development Board
ISD	Independent School District
M/F	Multi-Family
NPFGC	National Public Finance Guarantee Corp.
PILOT	Payment in Lieu of Taxes
PSF-GTD	Permanent School Fund Guaranteed
RB	Revenue Bonds
S/F	Single-Family
SBPA	Stand-by Bond Purchase Agreements
Syncora	Syncora Guarantee
VRDN	Variable Rate Demand Notes

• Fair Value Measurements - Various inputs are used in determining the fair value of investments. These inputs to valuation techniques are categorized into a disclosure hierarchy consisting of three broad levels for financial reporting purposes as follows:

• Level 1 — unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Fund has the ability to access

• Level 2 — other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)

• Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Fund's own assumptions used in determining the fair value of investments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety.

Changes in valuation techniques may result in transfers into or out of an assigned level within the disclosure hierarchy. In accordance with the Fund's policy, transfers between different levels of the fair value disclosure hierarchy are deemed to have occurred as of the beginning of the reporting period. The categorization of a value determined for investments is based on the pricing transparency of the investment and is not necessarily an indication of the risks associated with investing in those securities. For information about the Fund's policy regarding valuation of investments, please refer to the Fund's most recent financial statements as contained in its annual report.

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 14

Schedule of Investments (concluded) BlackRock National Municipal Fund

The following table summarizes the Fund's investments categorized in the disclosure hierarchy as of September 30, 2013:

	Level 1		Level 2		Level 3	Total
Assets:
Investments:
Long-Term Investments1	$	4,837,469	$	4,643,276,641	—	$	4,648,114,110
Short-Term Securities		35,341,649		176,575,000	—		211,916,649
Total	$	40,179,118	$	4,819,851,641	—	$	4,860,030,759

¹ See above Schedule of Investments for values in each state or political subdivision.

Certain of the Fund's assets and liabilities are held at carrying amount, which approximates fair value for financial reporting purposes. As of September 30, 2013, such assets and liabilities are categorized within the disclosure hierarchy as follows:

	Level 1		Level 2		Level 3	Total
Assets:
Cash	$	4,095,110		—	—	$	4,095,110
Liabilities:
TOB trust certificates		—	$	(471,494,484)	—		(471,494,484)
Total	$	4,095,110	$	(471,494,484)	—	$	(467,399,374)

There were no transfers between levels during the period ended September 30, 2013.

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 15

Schedule of Investments September 30, 2013 (Unaudited)	BlackRock Short-Term Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama  — 0.9%
Alabama 21st Century Authority, Refunding RB, Series A, 4.00%, 6/01/15	$	2,000	$	2,106,580
Alabama Federal Aid Highway Finance Authority, RB, Grant Appreciation, 5.00%, 9/01/16		5,130		5,734,571
				7,841,151
Alaska  — 0.2%
Alaska Student Loan Corp., RB, Senior Series A, AMT, 5.00%, 6/01/16		2,000		2,145,200
Arizona  — 0.7%
Phoenix Civic Improvement Corp., Refunding RB:
Junior Lien Water System, 4.00%, 7/01/14		5,000		5,144,750
Transit Excise Tax, Light Rail Project, 5.00%, 7/01/16		1,000		1,116,730
				6,261,480
California  — 11.5%
California Pollution Control Financing Authority, RB, Waste Management, Inc. Project, Series A-1, Mandatory Put Bonds, AMT, 1.88%, 4/01/25 (a)		5,000		4,999,650
California Pollution Control Financing Authority, Refunding RB, USA Waste Services, Inc. Project, Series A, Mandatory Put Bonds, AMT, 2.63%, 6/01/18 (a)		3,000		3,026,880
California State Department of Water Resources, Refunding RB, Series M, 5.00%, 5/01/14		35,000		35,980,000
California Statewide Communities Development Authority, RB, Kaiser Permanente, Series A, 5.00%, 4/01/14		1,000		1,023,980
City of Long Beach California, Refunding RB, Series B, AMT (NPFGC), 5.50%, 5/15/14		5,215		5,386,626
East Bay Municipal Utility District, Refunding RB, Wastewater System, 0.39%, 6/01/38 (a)		1,500		1,500,090
Los Angeles Unified School District, GO, Refunding, Series A-1, 5.00%, 7/01/15		6,000		6,491,460
State of California, GO, Economic Recovery Bonds, Series A (NPFGC), 5.00%, 7/01/15		3,805		3,945,557
Municipal Bonds	Par (000)		Value
California (concluded)
State of California, GO, Refunding, Various Purpose:
5.00%, 10/01/14	$	2,565	$	2,688,684
5.00%, 4/01/15		10,360		11,088,826
5.00%, 4/01/16		10,000		11,086,800
5.00%, 9/01/16		3,000		3,372,390
5.00%, 2/01/17		10,000		11,359,500
(NPFGC), 5.00%, 9/01/16		1,380		1,551,299
				103,501,742
Connecticut  — 3.7%
Connecticut Municipal Electric Energy Cooperative, Refunding RB, Series A (AGC), 5.00%, 1/01/14 (b)		2,115		2,140,592
Connecticut Resources Recovery Authority, Refunding RB, Covanta Southeastern Connecticut Co. Project, Series A, AMT, 4.00%, 11/15/15		2,635		2,820,688
Connecticut State Development Authority, RB, Connecticut Light & Power Co., Series A, Mandatory Put Bonds, AMT, 1.55%, 5/01/31 (a)		13,200		13,332,792
State of Connecticut, GO, Economic Recovery, Series A, 5.00%, 1/01/14		7,280		7,369,398
State of Connecticut, RB, Special Tax Bonds, Transportation Infrastructure, Series A:
5.00%, 11/01/13		5,000		5,020,950
5.00%, 11/01/14		2,700		2,841,453
				33,525,873
Delaware  — 1.3%
Delaware Transportation Authority, Refunding RB, Senior, 5.00%, 7/01/15		1,945		2,102,895
University of Delaware, Refunding RB, Series C, 0.70%, 11/01/37 (a)		10,000		9,942,200
				12,045,095
District of Columbia  — 0.6%
Metropolitan Washington Airports Authority, RB, Series A, AMT (NPFGC), 5.25%, 10/01/13		5,000		5,000,700

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 1

Schedule of Investments (continued)	BlackRock Short-Term Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Florida  — 5.7%
Citizens Property Insurance Corp., RB, Senior Secured Series A-1:
Coastal Account, 5.00%, 6/01/15	$	7,745	$	8,277,314
Personal Lines & Commercial Lines Account, 5.00%, 6/01/16		10,000		11,006,800
City of Jacksonville Florida, Refunding RB, Series C, 5.00%, 10/01/16		1,280		1,435,930
County of Broward Florida Airport System, ARB, Series Q-1, 5.00%, 10/01/15		1,000		1,086,630
County of Miami-Dade Florida, Refunding ARB, Series A, AMT:
4.00%, 10/01/14		2,500		2,590,500
4.00%, 10/01/15		2,750		2,923,938
5.00%, 10/01/16		1,750		1,945,685
Florida State Board of Education, GO, Refunding, Series A, 5.00%, 1/01/15		7,395		7,834,041
Florida State Department of Environmental Protection, Refunding RB, Series A:
Everglades Restoration (AGC), 5.00%, 7/01/16		1,205		1,340,779
Florida Forever, 5.00%, 7/01/14		5,000		5,178,300
Greater Orlando Aviation Authority, Refunding RB, Airport Facilities, Series A, AMT (AGM), 5.00%, 10/01/14		2,500		2,615,500
Highlands County Health Facilities Authority, Refunding RB, Adventist Health System/Sunbelt Obligated Group, Series I, 5.00%, 11/15/16		1,035		1,162,481
State of Florida, GO, Refunding, Department of Transportation, Full Faith and Credit, Right-of-Way Acquisition and Bridge Construction, Series B, 5.00%, 7/01/16		3,375		3,773,891
				51,171,789
Hawaii  — 0.7%
State of Hawaii, GO, Refunding, Series DG (AMBAC), 5.00%, 7/01/16		1,290		1,388,337
Municipal Bonds	Par (000)		Value
Hawaii (concluded)
State of Hawaii, Refunding RB, Airport System, AMT, 5.00%, 7/01/14	$	5,000	$	5,171,900
				6,560,237
Idaho  — 1.0%
Idaho Housing & Finance Association, RB, Unemployment Compensation, 5.00%, 8/15/14		8,585		8,939,561
Illinois  — 2.9%
City of Chicago Illinois, Refunding GARB, O’Hare International Airport, Senior Lien, Series A, AMT, 5.00%, 1/01/16		4,500		4,904,145
Illinois Finance Authority, Refunding RB, Hospital Sisters Services, Inc., Series C:
3.00%, 8/15/14		1,340		1,370,217
5.00%, 8/15/15		1,000		1,076,790
Regional Transit Authority, GO, Refunding, ERS, Series B, 0.70%, 6/01/25 (a)		16,300		16,300,000
State of Illinois, RB, Unemployment Insurance Fund Building Receipts, Series A, 5.00%, 6/15/16		2,500		2,775,225
				26,426,377
Indiana  — 1.1%
City of Whiting Indiana, RB, BP Products North America, Inc., Mandatory Put Bonds, 2.80%, 6/01/44 (a)		3,325		3,374,975
Indiana Finance Authority, RB, Water Utilities, Citizens Energy Group Project, Second Lien, Series B, 3.00%, 10/01/14		5,000		5,126,300
Indiana Finance Authority, Refunding RB, Marquette Project, 5.00%, 3/01/16		1,425		1,495,537
				9,996,812
Iowa  — 0.6%
Iowa Higher Education Loan Authority, Refunding RB, Private College Facility, 4.00%, 12/01/13		1,150		1,157,394
Iowa Student Loan Liquidity Corp., Refunding RB, Senior Series A-1, AMT, 3.10%, 12/01/14		4,525		4,629,211
				5,786,605

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 2

Schedule of Investments (continued)	BlackRock Short-Term Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Louisiana  — 2.9%
Parish of Morehouse Louisiana, Refunding RB, Pollution Control, International Paper Co. Project, Series A, 5.25%, 11/15/13	$	8,525	$	8,567,284
State of Louisiana, GO, Refunding, Series A (NPFGC), 5.00%, 8/01/14		12,000		12,485,400
Tobacco Settlement Financing Corp., Refunding RB, Series A:
5.00%, 5/15/16		3,000		3,271,260
5.00%, 5/15/17		1,730		1,921,788
				26,245,732
Maryland  — 2.2%
Maryland State Transportation Authority, Refunding RB, Baltimore/Washington Thurgood Marshall Airport Project:
4.00%, 3/01/14		3,170		3,219,357
AMT, 4.00%, 3/01/14		7,675		7,793,885
AMT, 5.00%, 3/01/16		8,315		9,134,776
				20,148,018
Massachusetts  — 4.0%
City of Boston Massachusetts, GO, Refunding, Series B, 4.00%, 2/01/15		6,580		6,909,329
Commonwealth of Massachusetts, GO, Consolidated Loan, Series B, 5.00%, 8/01/15		2,500		2,713,750
Commonwealth of Massachusetts, GO, Refunding, Consolidated Loan, Series D (NPFGC), 6.00%, 11/01/13		5,000		5,025,300
Massachusetts Port Authority, RB, Series A, AMT, 5.00%, 7/01/16		1,625		1,805,034
Massachusetts State Department of Transportation, Refunding RB, Senior Series B, 5.00%, 1/01/14		12,155		12,300,738
University of Massachusetts Building Authority, RB, Senior Series 1, 5.00%, 11/01/13		7,555		7,586,429
				36,340,580
Michigan  — 3.7%
Michigan Finance Authority, Refunding RB, Unemployment Obligation Assessment, Series A:
5.00%, 1/01/14		1,000		1,012,170
5.00%, 7/01/15		7,000		7,556,710
5.00%, 1/01/16		13,525		14,838,548
Municipal Bonds	Par (000)		Value
Michigan (concluded)
State of Michigan Trunk Line, Refunding RB, Series B (AGM), 5.00%, 9/01/15	$	7,825	$	8,492,003
Utica Community Schools, GO, Refunding, School Building & Site (Q-SBLF), 3.00%, 5/01/14		1,380		1,401,997
				33,301,428
Minnesota  — 0.7%
State of Minnesota, GO, Refunding, Various Purpose, Series D, 5.00%, 8/01/14		6,000		6,241,740
Nebraska  — 0.5%
Nebraska Public Power District, Refunding RB, General:
Series A, 5.00%, 1/01/16		1,000		1,097,590
Series B-1 (NPFGC), 5.00%, 1/01/14		3,000		3,036,600
				4,134,190
Nevada  — 2.3%
Clark County Nevada, Refunding RB, Motor Vehicle Fuel Tax, 5.00%, 7/01/15		8,000		8,628,960
Clark County Nevada School District, GO, Limited Tax, Series A, 5.00%, 6/15/16		11,000		12,201,530
				20,830,490
New Hampshire  — 0.2%
State of New Hampshire, RB, Federal Highway, GAN, 5.00%, 9/01/16		1,250		1,401,300
New Jersey  — 8.7%
County of Ocean New Jersy, GO, Refunding, 5.00%, 8/01/16		1,235		1,382,607
New Jersey Building Authority, Refunding RB, Series A, 5.00%, 6/15/15		13,880		14,941,404
New Jersey EDA, RB, School Facilities Construction, Series G (SIFMA Index Notes), 0.65%, 2/01/15 (a)		3,000		3,001,560
New Jersey EDA, Refunding RB:
Cigarette Tax, 5.00%, 6/15/14		4,000		4,116,880
School Facilities Construction, Series EE, 5.00%, 9/01/15		1,650		1,791,653

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 3

Schedule of Investments (continued)	BlackRock Short-Term Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
New Jersey (concluded)
New Jersey Health Care Facilities Financing Authority, Refunding RB:
Barnabas Health, Series A, 5.00%, 7/01/14	$	7,250	$	7,466,267
Barnabas Health, Series A, 5.00%, 7/01/16		1,000		1,090,900
Meridian Health System, 5.00%, 7/01/14		2,000		2,066,440
New Jersey Housing & Mortgage Finance Agency, Refunding RB, M/F Housing, Series 4, AMT, 0.90%, 5/01/15		9,500		9,501,235
New Jersey State Turnpike Authority, Refunding RB, Series C, 0.55%, 1/01/17 (a)		8,000		7,914,240
New Jersey Transportation Trust Fund Authority, RB:
Series B, 5.00%, 6/15/15		1,825		1,965,525
Transportation System, 5.75%, 6/15/16		6,275		7,096,900
State of New Jersey, GO, Refunding, Series O, 5.00%, 8/01/16		2,300		2,578,484
State of New Jersey, GO, Tax-Exempt, Various Purposes, 5.00%, 6/01/16		12,075		13,466,764
				78,380,859
New Mexico  — 0.3%
Albuquerque Bernalillo County Water Utility Authority, Refunding RB, Series B (c):
5.00%, 7/01/15		1,500		1,621,215
5.00%, 7/01/16		1,000		1,116,730
				2,737,945
New York  — 12.3%
City of New York New York, GO, Refunding, Series F, 5.00%, 8/01/15		6,000		6,507,060
Metropolitan Transportation Authority, RB:
Series A, 2.50%, 11/15/13		3,620		3,630,534
Series B, 5.00%, 11/15/14		1,000		1,052,020
Metropolitan Transportation Authority, Refunding RB:
Series A (AMBAC), 5.50%, 11/15/14		1,000		1,057,620
Series D, 4.00%, 11/15/15		1,400		1,500,674
Municipal Bonds	Par (000)		Value
New York (continued)
New York City Transitional Finance Authority, RB, Future Tax Secured:
Sub-Series A, 5.00%, 8/01/16	$	4,880	$	5,482,143
Sub-Series C-1, 5.00%, 11/01/15		4,860		5,328,504
Sub-Series F-1, 5.00%, 5/01/15		2,000		2,149,960
Sub-Series I, 2.00%, 5/01/15		11,870		12,196,781
New York City Transitional Finance Authority, Refunding RB, Future Tax Secured:
Sub-Series A, 5.00%, 11/01/15		5,455		5,980,862
Sub-Series E, 5.00%, 11/01/13		2,000		2,008,400
New York State Dormitory Authority, RB, General Purpose:
Series A, 5.00%, 3/15/15		5,560		5,945,364
Series B, 5.00%, 3/15/17		3,600		4,101,696
New York State Dormitory Authority, Refunding RB, NYU Hospital Center, Series A:
5.00%, 7/01/14		1,945		2,014,281
5.00%, 7/01/15		1,500		1,615,995
5.00%, 7/01/16		1,000		1,106,310
New York State HFA, RB, Affordable Housing, Series F (SONYMA), 0.75%, 5/01/15		2,000		1,998,660
New York State Local Government Assistance Corp., Refunding RB, Sub-Lien, Series A, 5.00%, 4/01/15		7,000		7,501,200
New York State Thruway Authority, RB, Second General Highway & Bridge Trust Fund Bonds, Series B, 5.00%, 4/01/15		2,150		2,300,565
New York State Thruway Authority, Refunding RB, General, Series I, 5.00%, 1/01/16		500		549,150
New York State Urban Development Corp., RB, Personal Income Tax, Series C, 5.00%, 3/15/17		6,470		7,371,659
New York State Urban Development Corp., Refunding RB, Personal Income Tax, Series D, 5.00%, 3/15/15		7,335		7,843,389
Port Authority of New York & New Jersey, RB, Consolidated, 169th Series, AMT, 5.00%, 10/15/15		2,680		2,918,788

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 4

Schedule of Investments (continued)	BlackRock Short-Term Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
New York (concluded)
Port Authority of New York & New Jersey, Refunding RB, Consolidated, 177th Series, AMT, 4.00%, 7/15/15	$	10,000	$	10,612,900
State of New York, GO, Refunding, Series C, 5.00%, 4/15/16		7,675		8,554,094
				111,328,609
North Carolina  — 1.9%
North Carolina Capital Facilities Finance Agency, Refunding RB, High Point University, 4.00%, 5/01/16		1,770		1,872,270
North Carolina Medical Care Commission, Refunding RB, Healthcare Facilities Revenue, WakeMed, Series A, 4.00%, 10/01/15		730		776,691
North Carolina Municipal Power Agency No. 1, Refunding RB, Catawba Electric, Series A:
5.00%, 1/01/16		3,500		3,833,270
5.25%, 1/01/17		5,000		5,666,300
State of North Carolina, Refunding RB, Series B, 4.00%, 11/01/14		4,905		5,106,939
				17,255,470
Oklahoma  — 1.3%
Cleveland County Educational Facilities Authority, LRB, Moore Public Schools Project:
5.00%, 6/01/15		2,050		2,187,965
5.00%, 6/01/16		845		927,160
Oklahoma Turnpike Authority, Refunding RB, Second Senior Series A, 5.00%, 1/01/15		7,875		8,332,301
				11,447,426
Oregon  — 0.6%
City of Portland Oregon, Refunding RB, Second Lien, Series A, 5.00%, 3/01/14		4,950		5,050,287
Pennsylvania  — 5.0%
City of Philadelphia Pennsylvania, Refunding ARB, Series A, AMT, 5.00%, 6/15/15		2,550		2,723,629
Commonwealth of Pennsylvania, GO, First Series, 5.00%, 6/01/15		7,980		8,599,408
Commonwealth of Pennsylvania, GO, Refunding, First Series (NPFGC), 5.00%, 2/01/15		7,605		7,725,539
Municipal Bonds	Par (000)		Value
Pennsylvania (concluded)
Pennsylvania Economic Development Financing Authority, RB, Waste Management, Inc. Project, 1.75%, 12/01/33 (a)	$	4,500	$	4,480,920
Pennsylvania Economic Development Financing Authority, Refunding RB, Series A:
5.00%, 7/01/15		10,000		10,819,100
5.00%, 1/01/16		6,000		6,606,900
Pennsylvania IDA, Refunding RB, Economic Development, 5.00%, 7/01/15		2,500		2,693,800
State Public School Building Authority, RB, School District of Philadelphia Project, 5.00%, 4/01/15		1,710		1,821,800
				45,471,096
South Carolina  — 0.9%
South Carolina Transportation Infrastructure Bank, Refunding RB (AMBAC):
Series A, 5.00%, 10/01/15		5,440		5,928,349
Series B, 5.25%, 10/01/14		2,000		2,099,820
				8,028,169
Tennessee  — 0.9%
Metropolitan Government of Nashville & Davidson County Tennessee, Refunding RB, (NPFGC), 5.00%, 1/01/14		8,110		8,208,942
Texas  — 3.4%
City of El Paso Texas, Refunding RB, Series A, 4.00%, 3/01/14		2,000		2,031,700
City of Houston Texas, Refunding ARB, Sub-Lien:
Series A, AMT, 5.00%, 7/01/14		4,000		4,139,080
Series B, 5.00%, 7/01/14		1,500		1,552,395
Comal ISD Texas, GO, Refunding, Unlimited Tax, Series A (PSF-GTD), 4.00%, 2/01/16		1,500		1,621,260
County of Harris Texas, Refunding RB, Toll Road, Senior Lien, Series B-1 (NPFGC), 5.00%, 8/15/14		1,295		1,348,471
Dallas ISD, GO, Refunding, (PSF-GTD), 4.00%, 2/15/15		2,200		2,313,102
Dallas/Fort Worth International Airport, Refunding RB, Series F, 3.00%, 11/01/14		2,850		2,934,730

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 5

Schedule of Investments (continued)	BlackRock Short-Term Municipal Fund
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Texas (concluded)
Harris County Cultural Education Facilities Finance Corp., Refunding RB:
Memorial Hermann Health System, Series A, 4.00%, 12/01/16	$	525	$	571,368
Methodist Hospital System, Series B, 5.25%, 12/01/14		2,600		2,744,638
Lower Colorado River Authority, Refunding RB:
5.00%, 5/15/14 (b)		15		15,449
5.00%, 5/15/14 (b)		50		51,476
5.00%, 5/15/14		4,935		5,081,767
5.00%, 5/15/16		2,490		2,760,862
Series A, 5.00%, 5/15/14		3,590		3,694,182
				30,860,480
Virginia  — 3.4%
County of Chesterfield Virginia, GO, Refunding, Series B, 5.00%, 1/01/15		2,810		2,977,560
Fairfax County Virginia, GO, Public Improvement, Series D, 5.00%, 10/01/13		4,000		4,000,520
Virginia College Building Authority, RB, 21st Century College & Equipment Programs, Series A:
5.00%, 2/01/15		6,210		6,599,988
5.00%, 2/01/16		11,910		13,140,303
Virginia Public School Authority, RB, Series I, 5.00%, 4/15/15		3,970		4,256,317
				30,974,688
Washington  — 1.1%
City of Seattle Washington, Refunding RB, Improvement, Series B, 5.00%, 2/01/14		10,000		10,162,400
Municipal Bonds	Par (000)		Value
Wisconsin  — 1.5%
State of Wisconsin, GO, Refunding, Series 1 (NPFGC), 5.00%, 5/01/16	$	2,500	$	2,672,850
State of Wisconsin, Refunding RB, Series 1, 5.00%, 7/01/16		10,000		11,158,600
				13,831,450
Total Long-Term Investments (Cost — $798,009,875) — 88.7%				801,583,921
Short-Term Securities
California  — 0.9%
State of California, RB, RAN, Series A-1, 2.00%, 5/28/14		8,000		8,095,670
	Shares
Money Market  Funds — 10.4%
FFI Institutional Tax-Exempt Fund, 0.03% (d)(e)		93,775,435		93,775,435
Total Short-Term Securities (Cost — $101,871,105) — 11.3%				101,871,105
Total Investments (Cost — $899,880,980*) — 100.0%				903,455,026
Other Assets Less Liabilities — 0.0%				80,349
Net Assets — 100.0%			$	903,535,375
* As of September 30, 2013, gross unrealized appreciation and gross unrealized depreciation based on cost for federal   income tax purposes were as follows:
Tax cost			$	899,880,980
Gross unrealized appreciation			$	3,920,712
Gross unrealized depreciation				(346,666	)
Net unrealized appreciation			$	3,574,046

Notes to Schedule of Investments

(a) Variable rate security. Rate shown is as of report date.

(b) Security is collateralized by municipal or US Treasury obligations.

(c) When-issued security. Unsettled when-issued transactions were as follows:

Counterparty		Value		Unrealized Appreciation
J.P. Morgan Securities LLC	$	2,737,945	$	12,595

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 6

Schedule of Investments (continued) BlackRock Short-Term Municipal Fund

(d) Investments in issuers considered to be an affiliate of the Fund during the period ended September 30, 2013, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliate	Shares Held at June 30, 2013	Net Activity	Shares Held at September 30, 2013	Income
FFI Institutional Tax-Exempt Fund	3,026,240	90,749,195	93,775,435	$   1,618

(e) Represents the current yield as of report date.

Portfolio Abbreviations

To simplify the listings of portfolio holdings in the Schedule of Investments, the names and descriptions of many of the securities have been abbreviated according to the following list:

AGC	Assured Guarantee Corp.
AGM	Assured Guaranty Municipal Corp.
AMBAC	American Municipal Bond Assurance Corp.
AMT	Alternative Minimum Tax (subject to)
ARB	Airport Revenue Bonds
EDA	Economic Development Authority
ERS	Extendible Reset Securities
GAN	Grant Anticipation Notes
GARB	General Airport Revenue Bonds
GO	General Obligation Bonds
HFA	Housing Finance Agency
IDA	Industrial Development Authority
ISD	Independent School District
LRB	Lease Revenue Bonds
M/F	Multi-Family
NPFGC	National Public Finance Guarantee Corp.
PSF-GTD	Permanent School Fund Guaranteed
Q-SBLF	Qualified School Bond Loan Fund
RAN	Revenue Anticipation Notes
RB	Revenue Bonds
SIFMA	Securities Industry and Financial Markets Association
SONYMA	State of New York Mortgage Agency

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 7

Schedule of Investments (concluded) BlackRock Short-Term Municipal Fund

• Fair Value Measurements - Various inputs are used in determining the fair value of investments. These inputs to valuation techniques are categorized into a disclosure hierarchy consisting of three broad levels for financial reporting purposes as follows:

• Level 1 — unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Fund has the ability to access

• Level 2 — other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)

• Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Fund's own assumptions used in determining the fair value of investments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety.

Changes in valuation techniques may result in transfers into or out of an assigned level within the disclosure hierarchy. In accordance with the Fund's policy, transfers between different levels of the fair value disclosure hierarchy are deemed to have occurred as of the beginning of the reporting period. The categorization of a value determined for investments is based on the pricing transparency of the investment and is not necessarily an indication of the risks associated with investing in those securities. For information about the Fund's policy regarding valuation of investments, please refer to the Fund's most recent financial statements as contained in its annual report.

The following table summarizes the Fund's investments categorized in the disclosure hierarchy as of September 30, 2013:

	Level 1		Level 2		Level 3	Total
Assets:
Investments:
Long-Term Investments1		—	$	801,583,921	—	$	801,583,921
Short-Term Securities	$	93,775,435		8,095,670	—		101,871,105
Total	$	93,775,435	$	809,679,591	—	$	903,455,026

¹ See above Schedule of Investments for values in each state or political subdivision.

Certain of the Fund’s liabilities are held at carrying amount, which approximates fair value for financial reporting purposes. As of September 30, 2013, a bank overdraft of $694 is categorized as Level 2 within the disclosure hierarchy.

There were no transfers between levels during the period ended September 30, 2013.

BLACKROCK MUNICIPAL BOND FUND, INC. SEPTEMBER 30, 2013 8

Item 2 –	Controls and Procedures
2(a) –	The registrant’s principal executive and principal financial officers, or persons performing similar functions, 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 15d-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 Fund, Inc.
	By:	/s/ John M. Perlowski
		John M. Perlowski
		Chief Executive Officer (principal executive officer) of
		BlackRock Municipal Bond Fund, Inc.
	Date: November 25, 2013
	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/ John M. Perlowski
		John M. Perlowski
		Chief Executive Officer (principal executive officer) of
		BlackRock Municipal Bond Fund, Inc.
	Date: November 25, 2013
	By:	/s/ Neal J. Andrews
		Neal J. Andrews
		Chief Financial Officer (principal financial officer) of
		BlackRock Municipal Bond Fund, Inc.
	Date: November 25, 2013

EX-99.CERT

EX-99. CERT

CERTIFICATION PURSUANT TO RULE 30a-2(a) UNDER THE 1940 ACT AND SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, John M. Perlowski, Chief Executive Officer (principal executive officer) of BlackRock Municipal Bond Fund, Inc., certify that:

1.I have reviewed this report on Form N-Q of BlackRock Municipal Bond Fund, Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the schedules of investments included in this report fairly present in all material respects the investments of the registrant as of the end of the fiscal quarter for which the report is filed;

4.The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

a)designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report, based on such evaluation; and

d)disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5. The registrant's other certifying officer(s) and I have disclosed to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

a)all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize, and report financial information; and

b)any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: November 25, 2013

/s/ John M. Perlowski

John M. Perlowski

Chief Executive Officer (principal executive officer) of
BlackRock Municipal Bond Fund, Inc.

EX-99. CERT

CERTIFICATION PURSUANT TO RULE 30a-2(a) UNDER THE 1940 ACT AND SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Neal J. Andrews, Chief Financial Officer (principal financial officer) of BlackRock Municipal Bond Fund, Inc., certify that:

1.I have reviewed this report on Form N-Q of BlackRock Municipal Bond Fund, Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the schedules of investments included in this report fairly present in all material respects the investments of the registrant as of the end of the fiscal quarter for which the report is filed;

4.The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

a)designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report, based on such evaluation; and

d)disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.The registrant's other certifying officer(s) and I have disclosed to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

a)all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize, and report financial information; and

b)any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: November 25, 2013

/s/ Neal J. Andrews

Neal J. Andrews

Chief Financial Officer (principal financial officer) of
BlackRock Municipal Bond Fund, Inc.