PAGE 1
000 A000000 02/28/2010
000 C000000 0001160864
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 CORE BOND TRUST
001 B000000 811-10543
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 COMPUTERSHARE TRUST COMPANY, N.A.
012 B000001 85-11340
012 C010001 PROVIDENCE
012 C020001 RI
012 C030001 02940
013 A000001 DELOITTE & TOUCHE LLP
013 B010001 PRINCETON
PAGE 2
013 B020001 NJ
013 B030001 08540
014 A000001 BB & T AM DISTRIBUTORS, INC.
014 B000001 8-52396
014 A000002 BLACKROCK CAPITAL MARKETS, LLC
014 B000002 8-67827
014 A000003 BLACKROCK DISTRIBUTORS, INC.
014 B000003 8-48775
014 A000004 BLACKROCK INVESTMENTS, LLC
014 B000004 8-48436
014 A000005 HARRIS WILLIAMS LLC
014 B000005 8-53380
014 A000006 MGI FUNDS DISTRIBUTOR, INC.
014 B000006 8-46960
014 A000007 NATCITY INVESTMENTS, INC.
014 B000007 8-35288
014 A000008 NORTHERN FUNDS DISTRIBUTORS, LLC
014 B000008 8-51242
014 A000009 PNC CAPITAL MARKETS, INC.
014 B000009 8-32493
014 A000010 PNC INVESTMENTS LLC
014 B000010 8-66195
014 A000011 PFPC DISTRIBUTORS, INC.
014 B000011 8-45467
014 A000012 RED CAPITAL MARKETS, INC.
014 B000012 8-31175
014 A000013 BLACKROCK EXECUTION SERVICES
014 B000013 8-48719
014 A000014 BLACKROCK FUND DISTRIBUTION COMPANY
014 B000014 8-67795
015 A000001 STATE STREET BANK AND TRUST COMPANY
015 B000001 C
015 C010001 BOSTON
015 C020001 MA
015 C030001 02111
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
015 A000004 STATE STREET TRUST COMPANY CANADA
015 B000004 S
015 C010004 CANADA
PAGE 3
015 D010004 CANADA
015 E010004 X
015 A000005 MIZUHO CORPORATE BANK, LTD.
015 B000005 S
015 C010005 TOKYO
015 D010005 JAPAN
015 E040005 X
015 A000006 SUMITOMO MITSUI BANKING CORPORATION
015 B000006 S
015 C010006 JAPAN
015 D010006 JAPAN
015 E040006 X
015 A000007 SKANDINAVISKA ENSKILDA BANKEN AB
015 B000007 S
015 C010007 SWEDEN
015 D010007 SWEDEN
015 E040007 X
015 A000008 STATE STREET BANK AND TRUST
015 B000008 S
015 C010008 UNITED KINGDOM
015 D010008 UNITED KINGDOM
015 E010008 X
018 000000 Y
019 A000000 Y
019 B000000 282
019 C000000 BLKRKADVSR
020 A000001 CITIGROUP GLOBAL MARKETS, INC.
020 B000001 11-2418191
020 C000001 41
020 A000002 UBS SECURITIES LLC
020 B000002 13-3873456
020 C000002 8
020 A000003 GOLDMAN, SACHS & CO.
020 B000003 13-5108880
020 C000003 4
020 A000004 MORGAN STANLEY & CO. INCORPORATED
020 B000004 13-2655998
020 C000004 2
020 A000005 CREDIT SUISSE SECURITIES (USA) L.L.C.
020 B000005 13-5659485
020 C000005 1
020 A000006 BANC OF AMERICA SECURITES LLC
020 B000006 56-2058405
020 C000006 1
020 A000007 RBS SECURITIES INC.
020 C000007 1
020 A000008 BARCLAYS CAPITAL INC.
020 C000008 1
020 A000009 J.P. MORGAN SECURITIES INC.
020 B000009 13-3299429
020 C000009 1
PAGE 4
020 A000010 DEUTSCHE BANK SECURITIES INC.
020 B000010 13-2730828
020 C000010 1
021 000000 61
022 A000001 GOLDMAN, SACHS & CO.
022 B000001 13-5108880
022 C000001 562948
022 D000001 430291
022 A000002 BARCLAYS CAPITAL INC.
022 C000002 281692
022 D000002 284190
022 A000003 MORGAN STANLEY & CO. INCORPORATED
022 B000003 13-2655998
022 C000003 231840
022 D000003 202419
022 A000004 DEUTSCHE BANK SECURITIES INC.
022 B000004 13-2730828
022 C000004 221419
022 D000004 206755
022 A000005 BANC OF AMERICA SECURITIES LLC
022 B000005 56-2058405
022 C000005 191248
022 D000005 180634
022 A000006 CITIGROUP GLOBAL MARKETS, INC.
022 B000006 11-2418191
022 C000006 102100
022 D000006 248221
022 A000007 CREDIT SUISSE SECURITIES (USA) L.L.C.
022 B000007 13-5659485
022 C000007 173409
022 D000007 154563
022 A000008 J.P. MORGAN SECURITIES INC.
022 B000008 13-3299429
022 C000008 111470
022 D000008 75570
022 A000009 BLK LIQUIDITY FUNDS, TEMPFUND, INSTIT. CLASS
022 B000009 52-0983343
022 C000009 66833
022 D000009 77568
022 A000010 NAVIGATE ADVISORS LLC
022 C000010 64502
022 D000010 66147
023 C000000 2152900
023 D000000 2041176
024 000000 Y
025 A000001 JPMORGAN CHASE & CO.
025 C000001 D
025 D000001 5820
025 A000002 CITIGROUP FUNDING, INC.
025 C000002 D
025 D000002 4269
PAGE 5
025 A000003 MORGAN STANLEY
025 C000003 D
025 D000003 3301
025 A000004 CITIBANK NA
025 C000004 D
025 D000004 2297
025 A000005 JPMORGAN SECURITIES INC.
025 C000005 D
025 D000005 1146
025 A000006 CREDIT SUISSE
025 C000006 D
025 D000006 628
025 A000007 CREDIT SUISSE GUERNSEY LTD.
025 C000007 D
025 D000007 430
025 D000008 0
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 6
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 Y
055 B000000 Y
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 -0.5
062 L000000 5.5
062 M000000 20.8
062 N000000 30.3
062 O000000 0.0
062 P000000 71.1
062 Q000000 32.0
062 R000000 -20.2
063 A000000 0
063 B000000 18.2
PAGE 7
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 Y
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 Y
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 N
070 Q010000 N
070 Q020000 N
070 R010000 Y
070 R020000 N
071 A000000 1387752
071 B000000 1330007
071 C000000 495804
071 D000000 268
072 A000000 6
072 B000000 14085
072 C000000 0
PAGE 8
072 D000000 0
072 E000000 126
072 F000000 1356
072 G000000 44
072 H000000 0
072 I000000 6
072 J000000 25
072 K000000 0
072 L000000 52
072 M000000 22
072 N000000 4
072 O000000 0
072 P000000 400
072 Q000000 0
072 R000000 31
072 S000000 24
072 T000000 0
072 U000000 0
072 V000000 0
072 W000000 61
072 X000000 2025
072 Y000000 1
072 Z000000 12187
072AA000000 31314
072BB000000 9720
072CC010000 9475
072CC020000 0
072DD010000 16160
072DD020000 0
072EE000000 0
073 A010000 0.5980
073 A020000 0.0000
073 B000000 0.0000
073 C000000 0.0000
074 A000000 2429
074 B000000 0
074 C000000 19145
074 D000000 541393
074 E000000 48
074 F000000 122
074 G000000 0
074 H000000 0
074 I000000 8099
074 J000000 132357
074 K000000 0
074 L000000 58143
074 M000000 913
074 N000000 762649
074 O000000 169010
074 P000000 220
074 Q000000 11805
PAGE 9
074 R010000 148651
074 R020000 0
074 R030000 6712
074 R040000 75030
074 S000000 0
074 T000000 351221
074 U010000 27023
074 U020000 0
074 V010000 13.00
074 V020000 0.00
074 W000000 0.0000
074 X000000 19181
074 Y000000 250390
075 A000000 0
075 B000000 347506
076 000000 12.17
077 A000000 Y
077 O000000 Y
078 000000 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 09249E101
087 A030000 BHK
088 A000000 N
088 B000000 N
088 C000000 N
088 D000000 N
SIGNATURE NEAL J. ANDREWS
TITLE CFO