PAGE 1
000 B000000 05/31/2008
000 C000000 0001232860
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 6.1
000 J000000 A
001 A000000 BLK MUNI INTERMEDIATE DURATION FUND, INC.
001 B000000 811-21348
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
007 C010200 2
007 C010300 3
007 C010400 4
007 C010500 5
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
008 A000001 BLACKROCK ADVISORS, LLC
008 B000001 A
008 C000001 801-47710
008 D010001 WILMINGTON
008 D020001 DE
008 D030001 19809
008 A000002 BLACKROCK INVESTMENT MANAGEMENT, LLC
008 B000002 S
008 C000002 801-56972
008 D010002 PLAINSBORO
008 D020002 NJ
008 D030002 08536
012 A000001 COMPUTERSHARE TRUST COMPANY, N.A. (COMMON)
012 B000001 85-11340
012 C010001 PROVIDENCE
012 C020001 RI
012 C030001 02940
012 C040001 3010
012 A000002 BNY MELLON SHAREOWNER SERVICES (PREFERRED)
PAGE 2
012 B000002 85-05006
012 C010002 NEW YORK
012 C020002 NY
012 C030002 10286
013 A000001 DELOITTE & TOUCHE LLP
013 B010001 PRINCETON
013 B020001 NJ
013 B030001 08540
014 A000001 MLPF&S AND OTHER ML BROKER/DEALER AFFILIATES
014 B000001 8-7221
014 A000002 BLACKROCK INVESTMENTS, INC.
014 B000002 8-048436
014 A000003 NORTHERN FUNDS DISTRIBUTORS, LLC
014 B000003 8-051242
014 A000004 PNC CAPITAL MARKETS, INC.
014 B000004 8-32493
014 A000005 HARRIS WILLIAMS LLC
014 B000005 8-53380
014 A000006 PFPC DISTRIBUTORS, INC.
014 B000006 8-045467
014 A000007 MGI FUNDS DISTRIBUTOR, INC.
014 B000007 8-046960
014 A000008 BB & T AM DISTRIBUTORS, INC.
014 B000008 8-52396
014 A000009 BLACKROCK DISTRIBUTORS, INC.
014 B000009 8-048775
014 A000010 PNC INVESTMENTS LLC
014 B000010 8-066195
014 A000011 DSP MERRILL LYNCH LIMITED
014 B000011 8-00000
014 A000012 FAM DISTRIBUTORS, INC.
014 B000012 8-14663
014 A000013 FIRST REPUBLIC SECURITIES COMPANY, LLC
014 B000013 8-52973
014 A000014 GPC SECURITIES, INC.
014 B000014 8-30108
014 A000015 BERNDALE SECURITIES LIMITED
014 B000015 8-00000
015 A000001 STATE STREET BANK AND TRUST COMPANY
015 B000001 C
015 C010001 BOSTON
015 C020001 MA
015 C030001 02109
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
PAGE 3
015 B000003 S
015 C010003 NEW YORK
015 C020003 NY
015 C030003 10017
015 E010003 X
018 000000 Y
019 A000000 Y
019 B000000 301
019 C000000 BLKRKADVSR
020 A000001 RBS GREENWICH CAPITAL
020 C000001 1
020 A000002 JANNEY MONTGOMERY SCOTT LLC
020 B000002 23-0731260
020 C000002 0
020 C000003 0
020 C000004 0
020 C000005 0
020 C000006 0
020 C000007 0
020 C000008 0
020 C000009 0
020 C000010 0
021 000000 1
022 A000001 CITIGROUP GLOBAL MARKETS, INC.
022 B000001 11-2418191
022 C000001 61179
022 D000001 46945
022 A000002 J.P. MORGAN SECURITIES INC.
022 B000002 13-3224016
022 C000002 42616
022 D000002 60028
022 A000003 GOLDMAN. SACHS & CO.
022 B000003 13-5108880
022 C000003 46100
022 D000003 36680
022 A000004 MORGAN KEEGAN & COMPANY, INC.
022 B000004 64-0474907
022 C000004 40296
022 D000004 41433
022 A000005 LEHMAN BROTHERS INC.
022 B000005 13-2518466
022 C000005 30220
022 D000005 32600
022 A000006 BANC OF AMERICA SECURITIES LLC
022 B000006 56-2058405
022 C000006 11434
022 D000006 37578
022 A000007 BEAR, STEARNS & CO. INC.
022 B000007 13-3299429
022 C000007 29429
022 D000007 3471
PAGE 4
022 A000008 MORGAN STANLEY & CO. INCORPORATED
022 B000008 13-2655998
022 C000008 1729
022 D000008 24683
022 A000009 DEPFA FIRST ALBANY SECURITIES, LLC
022 B000009 43-2117279
022 C000009 7300
022 D000009 17803
022 A000010 UBS SECURITIES LLC
022 B000010 13-3873456
022 C000010 16052
022 D000010 6171
023 C000000 390713
023 D000000 398730
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
045 000000 Y
046 000000 N
047 000000 Y
048 000000 0.550
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
PAGE 5
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 9.6
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 0.0
062 M000000 0.0
062 N000000 0.0
062 O000000 156.3
062 P000000 0.0
062 Q000000 0.0
062 R000000 0.0
063 A000000 0
063 B000000 16.8
064 A000000 Y
PAGE 6
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
070 C020000 N
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 Y
070 N020000 N
070 O010000 Y
070 O020000 N
070 P010000 Y
070 P020000 Y
070 Q010000 N
070 Q020000 N
070 R010000 Y
070 R020000 N
071 A000000 129043
071 B000000 162288
071 C000000 891296
071 D000000 14
072 A000000 12
072 B000000 45411
072 C000000 0
072 D000000 0
072 E000000 0
PAGE 7
072 F000000 4864
072 G000000 226
072 H000000 0
072 I000000 45
072 J000000 45
072 K000000 0
072 L000000 57
072 M000000 42
072 N000000 13
072 O000000 0
072 P000000 976
072 Q000000 0
072 R000000 102
072 S000000 64
072 T000000 0
072 U000000 0
072 V000000 0
072 W000000 934
072 X000000 7368
072 Y000000 1327
072 Z000000 39370
072AA000000 1973
072BB000000 2968
072CC010000 0
072CC020000 22744
072DD010000 27842
072DD020000 0
072EE000000 0
073 A010000 0.7290
073 A020000 0.0000
073 B000000 0.0000
073 C000000 0.0000
074 A000000 51
074 B000000 0
074 C000000 52880
074 D000000 858310
074 E000000 0
074 F000000 0
074 G000000 0
074 H000000 0
074 I000000 0
074 J000000 0
074 K000000 291
074 L000000 15000
074 M000000 69
074 N000000 926601
074 O000000 0
074 P000000 311
074 Q000000 0
074 R010000 0
074 R020000 0
PAGE 8
074 R030000 0
074 R040000 56649
074 S000000 320226
074 T000000 549415
074 U010000 38035
074 U020000 0
074 V010000 14.45
074 V020000 0.00
074 W000000 0.0000
074 X000000 18338
074 Y000000 320000
075 A000000 0
075 B000000 881945
076 000000 13.70
077 A000000 Y
077 B000000 Y
078 000000 N
080 A000000 VIGILANT INSURANCE COMPANY
080 C000000 1000
081 A000000 Y
081 B000000 113
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 0
086 A020000 0
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 09253X102
087 A030000 MUI
087 B010000 PREFERRED STOCK
088 A000000 N
088 B000000 N
088 C000000 N
088 D000000 Y
SIGNATURE DONALD C. BURKE
TITLE PRESIDENT