BIE Blackrock Municipal Bond Investment Trust

000 B000000 08/31/2013
000 C000000 0001169028
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 6.1
000 J000000 A
001 A000000 BLACKROCK MUNICIPAL BOND INVESTMENT TRUST
001 B000000 811-21054
001 C000000 8004417762
002 A000000 100 BELLEVUE PARKWAY
002 B000000 WILMINGTON
002 C000000 DE
002 D010000 19809
003  000000 N
004  000000 N
005  000000 N
006  000000 N
007 A000000 N
007 B000000  0
007 C010100  1
008 A000001 BLACKROCK ADVISORS, LLC
008 B000001 A
008 C000001 801-47710
008 D010001 WILMINGTON
008 D020001 DE
008 D030001 19809
008 A000002 BLACKROCK FINANCIAL MANAGEMENT, INC.
008 B000002 S
008 C000002 801-48433
008 D010002 NEW YORK
008 D020002 NY
008 D030002 10055
012 A000001 COMPUTERSHARE TRUST COMPANY, N.A.
012 B000001 85-11340
012 C010001 CANTON
012 C020001 MA
012 C030001 02021
012 A000002 THE BANK OF NEW YORK MELLON (PREFERRED)
012 B000002 85-05006
012 C010002 NEW YORK
012 C020002 NY
012 C030002 10289
013 A000001 DELOITTE & TOUCHE LLP
013 B010001 BOSTON
013 B020001 MA
013 B030001 02116
014 A000001 BLACKROCK CAPITAL MARKETS, LLC
014 B000001 8-67827

014 A000002 BLACKROCK EXECUTION SERVICES
014 B000002 8-48719
014 A000003 BLACKROCK INVESTMENTS, LLC
014 B000003 8-48436
014 A000004 HARRIS WILLIAMS LLC
014 B000004 8-53380
014 A000005 PNC CAPITAL MARKETS, INC.
014 B000005 8-32493
014 A000006 PNC INVESTMENTS LLC
014 B000006 8-66195
015 A000001 STATE STREET BANK & TRUST COMPANY
015 B000001 C
015 C010001 BOSTON
015 C020001 MA
015 C030001 02110
015 E010001 X
015 A000002 THE BANK OF NEW YORK MELLON
015 B000002 S
015 C010002 NEW YORK
015 C020002 NY
015 C030002 10286
015 E010002 X
015 A000003 J.P. MORGAN CHASE BANK
015 B000003 S
015 C010003 NEW YORK
015 C020003 NY
015 C030003 10017
015 E010003 X
018  000000 Y
019 A000000 Y
019 B000000  290
019 C000000 BLKRKADVSR
020 A000001 BANK OF AMERICA CORP
020 B000001 56-0906609
020 C000001      0
021  000000        0
022 A000001 FFI INSTITUTIONAL TAX-EXEMPT FUND
022 B000001 22-2509978
022 C000001     19349
022 D000001     18129
022 A000002 PERSHING LLC
022 B000002 13-2741729
022 C000002      7969
022 D000002      6223
022 A000003 CITIGROUP GLOBAL MARKETS, INC.
022 B000003 11-2418191
022 C000003      3497
022 D000003      2896
022 A000004 STIFEL, NICOLAUS & COMPANY, INCORPORATED
022 B000004 43-0538770
022 C000004      1521

022 D000004      4019
022 A000005 BARCLAYS CAPITAL INC.
022 B000005 13-3299429
022 C000005      3254
022 D000005      1439
022 A000006 WELLS FARGO & CO
022 B000006 41-0449260
022 C000006      3844
022 D000006       833
022 A000007 MORGAN STANLEY & CO. INCORPORATED
022 B000007 13-2655998
022 C000007      2133
022 D000007      1904
022 A000008 J.P. MORGAN SECURITIES INC.
022 B000008 13-3299429
022 C000008      1465
022 D000008      2239
022 A000009 JANNEY MONTGOMERY SCOTT LLC
022 B000009 23-0731260
022 C000009       757
022 D000009      2836
022 A000010 RAYMOND JAMES FINANCIAL INC
022 B000010 59-1517485
022 C000010      1342
022 D000010       998
023 C000000      49208
023 D000000      49433
024  000000 N
026 A000000 N
026 B000000 N
026 C000000 N
026 D000000 Y
026 E000000 N
026 F000000 N
026 G010000 N
026 G020000 N
026 H000000 N
027  000000 N
028 A010000         0
028 A020000         0
028 A030000         0
028 A040000         0
028 B010000         0
028 B020000         0
028 B030000         0
028 B040000         0
028 C010000         0
028 C020000         0
028 C030000         0
028 C040000         0
028 D010000         0

028 D020000         0
028 D030000         0
028 D040000         0
028 E010000         0
028 E020000         0
028 E030000         0
028 E040000         0
028 F010000         0
028 F020000         0
028 F030000         0
028 F040000         0
028 G010000         0
028 G020000         0
028 G030000         0
028 G040000         0
028 H000000         0
030 A000000      0
030 B000000  0.00
030 C000000  0.00
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042 H000000   0
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044  000000      0
045  000000 Y
046  000000 N
047  000000 Y
048  000000  0.650
048 A010000        0
048 A020000 0.000
048 B010000        0
048 B020000 0.000
048 C010000        0
048 C020000 0.000
048 D010000        0
048 D020000 0.000
048 E010000        0
048 E020000 0.000
048 F010000        0

048 F020000 0.000
048 G010000        0
048 G020000 0.000
048 H010000        0
048 H020000 0.000
048 I010000        0
048 I020000 0.000
048 J010000        0
048 J020000 0.000
048 K010000        0
048 K020000 0.000
049  000000 N
050  000000 N
051  000000 N
052  000000 N
053 A000000 Y
053 B000000 Y
053 C000000 N
054 A000000 Y
054 B000000 Y
054 C000000 N
054 D000000 N
054 E000000 N
054 F000000 N
054 G000000 N
054 H000000 Y
054 I000000 N
054 J000000 Y
054 K000000 N
054 L000000 N
054 M000000 Y
054 N000000 N
055 A000000 N
055 B000000 N
056  000000 Y
057  000000 N
058 A000000 N
059  000000 Y
060 A000000 N
060 B000000 N
061  000000        0
062 A000000 Y
062 B000000   0.0
062 C000000   0.0
062 D000000   0.0
062 E000000   1.0
062 F000000   0.0
062 G000000   0.0
062 H000000   0.0
062 I000000   0.0
062 J000000   0.0

062 K000000   0.0
062 L000000   2.9
062 M000000   0.0
062 N000000   0.0
062 O000000 168.8
062 P000000   0.0
062 Q000000   0.0
062 R000000   0.0
063 A000000   0
063 B000000 23.6
064 A000000 Y
064 B000000 N
066 A000000 N
067  000000 N
068 A000000 N
068 B000000 N
069  000000 N
070 A010000 Y
070 A020000 N
070 B010000 N
070 B020000 N
070 C010000 Y
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070 D010000 N
070 D020000 N
070 E010000 Y
070 E020000 Y
070 F010000 N
070 F020000 N
070 G010000 Y
070 G020000 N
070 H010000 N
070 H020000 N
070 I010000 N
070 I020000 N
070 J010000 N
070 J020000 N
070 K010000 Y
070 K020000 Y
070 L010000 N
070 L020000 N
070 M010000 N
070 M020000 N
070 N010000 N
070 N020000 N
070 O010000 Y
070 O020000 N
070 P010000 Y
070 P020000 Y
070 Q010000 N
070 Q020000 N

070 R010000 N
070 R020000 N
071 A000000     28849
071 B000000     31079
071 C000000     90364
071 D000000   32
072 A000000 12
072 B000000     4093
072 C000000        0
072 D000000        0
072 E000000        0
072 F000000      599
072 G000000       15
072 H000000        0
072 I000000       20
072 J000000        8
072 K000000        0
072 L000000        7
072 M000000        6
072 N000000        8
072 O000000        0
072 P000000      200
072 Q000000        0
072 R000000       51
072 S000000       11
072 T000000        0
072 U000000        0
072 V000000        0
072 W000000      232
072 X000000     1157
072 Y000000       74
072 Z000000     3010
072AA000000        0
072BB000000      514
072CC010000        0
072CC020000     8101
072DD010000     3095
072DD020000        0
072EE000000        0
073 A010000   0.9270
073 A020000   0.0000
073 B000000   0.0000
073 C000000   0.0000
074 A000000        0
074 B000000        0
074 C000000      500
074 D000000    80425
074 E000000        0
074 F000000        0
074 G000000        0
074 H000000        0

074 I000000     1380
074 J000000      866
074 K000000        0
074 L000000        0
074 M000000      186
074 N000000    83357
074 O000000      822
074 P000000       41
074 Q000000        0
074 R010000        0
074 R020000        0
074 R030000        0
074 R040000    17047
074 S000000    17800
074 T000000    47647
074 U010000     3339
074 U020000        0
074 V010000    14.27
074 V020000     0.00
074 W000000   0.0000
074 X000000     2154
074 Y000000    18622
075 A000000        0
075 B000000    73069
076  000000    13.14
077 A000000 Y
077 B000000 Y
077 O000000 Y
078  000000 N
080 A000000 FEDERAL INSURANCE COMPANY
080 B000000 NATL UNION FIRE INSURANCE CO OF PITTSBURGH PA
080 C000000    72025
081 A000000 Y
081 B000000  90
082 A000000 N
082 B000000        0
083 A000000 N
083 B000000        0
084 A000000 N
084 B000000        0
085 A000000 Y
085 B000000 N
086 A010000      1
086 A020000     16
086 B010000      0
086 B020000      0
086 C010000      0
086 C020000      0
086 D010000      0
086 D020000      0
086 E010000      0

086 E020000      0
086 F010000      0
086 F020000      0
087 A010000 COMMON STOCK
087 A020000 09249K107
087 A030000 BIE
087 B010000 PREFERRED STOCK
088 A000000 N
088 B000000 N
088 C000000 N
088 D000000 Y
SIGNATURE   NEAL J. ANDREWS
TITLE       CFO