PAGE 1 000 B000000 08/31/2008 000 C000000 0001181187 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 INSURED MUNICIPAL INCOME TRUST 001 B000000 811-21178 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 FINANCIAL MANAGEMENT, INC. 008 B000002 S 008 C000002 801-48433 008 D010002 NEW YORK 008 D020002 NY 008 D030002 10022 012 A000001 COMPUTERSHARE TRUST COMPANIES, N.A. (COMMON) 012 B000001 85-05006 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& AND OTHER ML BROKER/DEALER AFFIATES 014 B000001 8-7221 014 A000002 BLACKROCK CAPITAL MARKETS, LLC 014 B000002 8-67827 014 A000003 BLACKROCK INVESTMENTS, INC. 014 B000003 8-048436 014 A000004 NORTHERN FUNDS DISTRIBUTORS, LLC 014 B000004 8-051242 014 A000005 PNC CAPITAL MARKETS, INC. 014 B000005 8-32493 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 HARRIS WILLIAMS LLC 014 B000011 8-53380 014 A000012 DSP MERRILL LYNCH LIMITED 014 B000012 8-00000 014 A000013 FAM DISTRIBUTORS, INC. 014 B000013 8-14663 014 A000014 FIRST REPUBLIC SECURITIES COMPANY, LLC 014 B000014 8-52973 014 A000015 GPC SECURITIES, INC. 014 B000015 8-30108 014 A000016 BERNDALE SECURITIES LIMITED 014 B000016 8-00000 015 A000001 STATE STREET BANK AND TRUST COMPANY 015 B000001 C 015 C010001 BOSTON 015 C020001 MA 015 C030001 02101 015 E010001 X 015 A000002 THE BANK OF NEW YORK MELLON 015 B000002 S 015 C010002 NEW YORK 015 C020002 NY 015 C030002 10286 PAGE 3 015 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 301 019 C000000 BLKRKADVSR 020 A000001 JANNEY MONTGOMERY SCOTT LLC 020 B000001 23-0731260 020 C000001 0 020 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 0 022 A000001 MERRILL LYNCH INSTITUTIONAL TAX-EXEMPT FUND 022 B000001 22-2509978 022 C000001 245400 022 D000001 243550 022 A000002 J.P. MORGAN SECURITIES INC. 022 B000002 13-3224016 022 C000002 50318 022 D000002 62164 022 A000003 UBS SECURITIES LLC 022 B000003 13-3873456 022 C000003 50333 022 D000003 57667 022 A000004 BANC OF AMERICA SECURITIES LLC 022 B000004 56-2058405 022 C000004 26602 022 D000004 63379 022 A000005 MORGAN STANLEY & CO. INCORPORATED 022 B000005 13-2655998 022 C000005 28953 022 D000005 52375 022 A000006 CITIGROUP GLOBAL MARKETS, INC. 022 B000006 11-2418191 022 C000006 35777 022 D000006 35019 022 A000007 WACHOVIA SECURITIES, LLC 022 B000007 54-0796506 022 C000007 7108 PAGE 4 022 D000007 31721 022 A000008 DEPFA FIRST ALBANY SECURITIES LLC 022 B000008 43-2117279 022 C000008 17380 022 D000008 13824 022 A000009 RAYMOND JAMES & ASSOCIATES, INC. 022 B000009 59-1237041 022 C000009 14765 022 D000009 15235 022 A000010 GOLDMAN, SACHS & CO. 022 B000010 13-5108880 022 C000010 22741 022 D000010 0 023 C000000 522811 023 D000000 608851 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 PAGE 5 048 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 Y 060 B000000 Y 061 000000 0 062 A000000 Y 062 B000000 0.0 062 C000000 0.0 062 D000000 0.0 062 E000000 0.0 062 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 0.0 062 M000000 0.0 062 N000000 0.0 062 O000000 160.3 062 P000000 0.0 062 Q000000 0.0 062 R000000 1.1 063 A000000 0 063 B000000 24.3 PAGE 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 070 C020000 N 070 D010000 N 070 D020000 N 070 E010000 Y 070 E020000 N 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 N 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 N 070 Q010000 N 070 Q020000 N 070 R010000 N 070 R020000 N 071 A000000 230328 071 B000000 244213 071 C000000 596761 071 D000000 39 072 A000000 12 072 B000000 30561 072 C000000 0 072 D000000 0 PAGE 7 072 E000000 334 072 F000000 3366 072 G000000 65 072 H000000 0 072 I000000 35 072 J000000 34 072 K000000 0 072 L000000 25 072 M000000 42 072 N000000 9 072 O000000 0 072 P000000 467 072 Q000000 0 072 R000000 50 072 S000000 112 072 T000000 0 072 U000000 0 072 V000000 0 072 W000000 563 072 X000000 4768 072 Y000000 1003 072 Z000000 27130 072AA000000 4609 072BB000000 10806 072CC010000 0 072CC020000 15128 072DD010000 19185 072DD020000 0 072EE000000 0 073 A010000 0.7320 073 A020000 0.0000 073 B000000 0.0000 073 C000000 0.0000 074 A000000 60 074 B000000 0 074 C000000 0 074 D000000 589900 074 E000000 0 074 F000000 0 074 G000000 0 074 H000000 0 074 I000000 4161 074 J000000 501 074 K000000 0 074 L000000 6107 074 M000000 92 074 N000000 600821 074 O000000 0 074 P000000 211 074 Q000000 0 074 R010000 0 PAGE 8 074 R020000 0 074 R030000 0 074 R040000 82483 074 S000000 149994 074 T000000 368133 074 U010000 26214 074 U020000 0 074 V010000 14.04 074 V020000 0.00 074 W000000 0.0000 074 X000000 11998 074 Y000000 151315 075 A000000 0 075 B000000 609849 076 000000 13.19 077 A000000 Y 077 B000000 Y 077 D000000 Y 077 O000000 Y 078 000000 N 080 A000000 VIGILANT INSURANCE COMPANY 080 C000000 900 081 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 10 086 A020000 138 086 B010000 0 086 B020000 0 086 C010000 0 086 C020000 0 086 D010000 3 086 D020000 79050 086 E010000 0 086 E020000 0 086 F010000 0 086 F020000 0 087 A010000 COMMON STOCK 087 A020000 092479104 087 A030000 BYM 087 B010000 PREFERRED STOCK 088 A000000 N 088 B000000 N 088 C000000 N PAGE 9 088 D000000 Y SIGNATURE DONALD C. BURKE TITLE PRESIDENT