PAGE 1 000 B000000 02/28/2011 000 C000000 0000896665 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 SENIOR HIGH INCOME FUND, INC. 001 B000000 811-07456 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 10055 012 A000001 BNY MELLON SHAREOWNER SERVICES 012 B000001 85-05006 012 C010001 JERSEY CITY 012 C020001 NJ 012 C030001 07310 013 A000001 DELOITTE & TOUCHE LLP 013 B010001 PRINCETON PAGE 2 013 B020001 NJ 013 B030001 08540 014 A000001 BLACKROCK CAPITAL MARKETS, LLC 014 B000001 8-67827 014 A000002 BLACKROCK EXECUTION SERVICES 014 B000002 8-48719 014 A000003 BLACKROCK FUND DISTRIBUTION COMPANY 014 B000003 8-67795 014 A000004 BLACKROCK INVESTMENTS, LLC 014 B000004 8-48436 014 A000005 HARRIS WILLIAMS LLC 014 B000005 8-53380 014 A000006 PNC CAPITAL MARKETS, INC. 014 B000006 8-32493 014 A000007 PNC INVESTMENTS LLC 014 B000007 8-66195 015 A000001 THE BANK OF NEW YORK MELLON 015 B000001 C 015 C010001 NEW YORK 015 C020001 NY 015 C030001 10286 015 E010001 X 015 A000002 J.P. MORGAN CHASE BANK 015 B000002 S 015 C010002 NEW YORK 015 C020002 NY 015 C030002 10017 015 E010002 X 015 A000003 CIBC MELLON TRUST CO 015 B000003 S 015 C010003 CANADA 015 D010003 CANADA 015 E040003 X 015 A000004 THE BANK OF NEW YORK MELLON 015 B000004 S 015 C010004 IRELAND 015 D010004 IRELAND 015 E010004 X 018 000000 Y 019 A000000 Y 019 B000000 294 019 C000000 BLKRKADVSR 020 A000001 JONESTRADING INSTITUTIONAL SERVICES LLC 020 B000001 51-0484896 020 C000001 5 020 A000002 BROADPOINT CAPITAL, INC. 020 B000002 11-2657332 020 C000002 1 020 A000003 UBS SECURITIES LLC 020 B000003 13-3873456 020 C000003 0 PAGE 3 020 A000004 OPPENHEIMER & CO. INC. 020 C000004 0 020 A000005 MORGAN STANLEY & CO. INCORPORATED 020 B000005 13-2655998 020 C000005 0 020 A000006 DEUTSCHE BANK SECURITIES INC. 020 B000006 13-2730828 020 C000006 0 020 A000007 KNIGHT LIBERTAS LLC 020 C000007 0 020 C000008 0 020 C000009 0 020 C000010 0 021 000000 6 022 A000001 BLK LIQUIDITY FUNDS, TEMPFUND, INSTIT. CLASS 022 B000001 52-0983343 022 C000001 159534 022 D000001 156120 022 A000002 J.P. MORGAN SECURITIES INC. 022 B000002 13-3299429 022 C000002 33561 022 D000002 19744 022 A000003 DEUTSCHE BANK SECURITIES INC. 022 B000003 13-2730828 022 C000003 34996 022 D000003 13745 022 A000004 CREDIT SUISSE SECURITIES (USA) L.L.C. 022 B000004 13-5659485 022 C000004 32448 022 D000004 11746 022 A000005 BARCLAYS CAPITAL INC. 022 C000005 24601 022 D000005 11602 022 A000006 MORGAN STANLEY & CO. INCORPORATED 022 B000006 13-2655998 022 C000006 18303 022 D000006 16370 022 A000007 BANC OF AMERICA SECURITIES LLC 022 B000007 56-2058405 022 C000007 22842 022 D000007 10011 022 A000008 CITIGROUP GLOBAL MARKETS, INC. 022 B000008 11-2418191 022 C000008 18640 022 D000008 11398 022 A000009 GOLDMAN, SACHS & CO. 022 B000009 13-5108880 022 C000009 17987 022 D000009 3314 022 A000010 MERRILL LYNCH, PIERCE, FENNER & SMITH INC. 022 B000010 13-5674085 PAGE 4 022 C000010 13696 022 D000010 3537 023 C000000 397466 023 D000000 289765 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 0.500 048 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 PAGE 5 054 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 Y 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 0.1 062 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 0.1 062 M000000 0.0 062 N000000 0.0 062 O000000 0.0 062 P000000 55.3 062 Q000000 70.3 062 R000000 2.5 063 A000000 0 063 B000000 6.9 064 A000000 N 064 B000000 Y 065 000000 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 PAGE 6 070 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 Y 070 J020000 N 070 K010000 Y 070 K020000 Y 070 L010000 Y 070 L020000 Y 070 M010000 Y 070 M020000 Y 070 N010000 Y 070 N020000 N 070 O010000 Y 070 O020000 Y 070 P010000 Y 070 P020000 Y 070 Q010000 N 070 Q020000 N 070 R010000 N 070 R020000 N 071 A000000 251078 071 B000000 228453 071 C000000 275557 071 D000000 83 072 A000000 12 072 B000000 20025 072 C000000 5 072 D000000 0 072 E000000 456 072 F000000 1350 072 G000000 51 072 H000000 0 072 I000000 56 072 J000000 33 072 K000000 0 072 L000000 32 072 M000000 25 072 N000000 20 PAGE 7 072 O000000 0 072 P000000 525 072 Q000000 0 072 R000000 57 072 S000000 133 072 T000000 0 072 U000000 0 072 V000000 0 072 W000000 306 072 X000000 2588 072 Y000000 2 072 Z000000 17900 072AA000000 7997 072BB000000 10980 072CC010000 20895 072CC020000 0 072DD010000 18480 072DD020000 0 072EE000000 0 073 A010000 0.2750 073 A020000 0.0000 073 B000000 0.0000 073 C000000 0.0000 074 A000000 101 074 B000000 0 074 C000000 0 074 D000000 299733 074 E000000 0 074 F000000 3888 074 G000000 0 074 H000000 0 074 I000000 4414 074 J000000 2808 074 K000000 0 074 L000000 3871 074 M000000 70 074 N000000 314885 074 O000000 25577 074 P000000 113 074 Q000000 50000 074 R010000 0 074 R020000 0 074 R030000 0 074 R040000 435 074 S000000 0 074 T000000 238760 074 U010000 56606 074 U020000 0 074 V010000 4.22 074 V020000 0.00 074 W000000 0.0000 PAGE 8 074 X000000 22978 074 Y000000 976 075 A000000 0 075 B000000 228516 076 000000 4.18 077 A000000 Y 077 B000000 Y 077 O000000 Y 078 000000 N 080 A000000 FEDERAL INSURANCE COMPANY 080 B000000 NATIONAL UNION FIRE INS. CO. OF PITTSBURGH,PA 080 C000000 71150 081 A000000 Y 081 B000000 96 082 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 63 086 A020000 256 086 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 09255T109 087 A030000 ARK 088 A000000 N 088 B000000 N 088 C000000 N 088 D000000 N SIGNATURE NEAL J. ANDREWS TITLE CFO