<PAGE> PAGE 1
000 A000000 04/30/98
000 C000000 0000018180
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0.a
000 J000000 U
001 A000000 CASTLE CONVERTIBLE FUND, INC.
001 B000000 811-2213
001 C000000 2128068800
002 A000000 75 MAIDEN LANE
002 B000000 NEW YORK
002 C000000 NY
002 D010000 10038
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 N
007 B000000 0
020 A000001 BAIRD PATRICK & CO.
020 B000001 13-7666571
020 C000001 4
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 4
022 A000001 MERRILL LYNCH PIERCE FENNER & SMITH INC
022 B000001 13-5674085
022 C000001 192750
022 D000001 7429
022 A000002 SHEARSON LEHMAN INC.
022 B000002 13-2518466
022 C000002 1350
022 D000002 1261
022 A000003 C.S. FIRST BOSTON
022 B000003 13-5659485
022 C000003 2272
022 D000003 0
022 A000004 DONALDSON LUFKIN & JENRETTE
022 B000004 13-2741729
022 C000004 1176
022 D000004 928
<PAGE> PAGE 2
022 A000005 BAIRD PATRICK & CO.
022 B000005 13-7666571
022 C000005 0
022 D000005 1943
022 A000006 J. P. MORGAN SECURITIES INC.
022 B000006 13-3224016
022 C000006 1649
022 D000006 0
022 A000007 MORGAN STANLEY & CO
022 B000007 13-2655998
022 C000007 1616
022 D000007 0
022 A000008 GOLDMAN SACHS & CO. INC.
022 B000008 13-5108880
022 C000008 1001
022 D000008 573
022 A000009 SOLOMON SMITH BARNEY
022 B000009 13-2082694
022 C000009 0
022 D000009 1563
022 A000010 JEFFRIES & CO., INC.
022 B000010 95-2622900
022 C000010 0
022 D000010 631
023 C000000 202010
023 D000000 15577
024 000000 Y
025 A000001 MERRILL LYNCH & CO., INC.
025 B000001 13-5674085
025 C000001 D
025 D000001 1199
025 D000002 0
025 D000003 0
025 D000004 0
025 D000005 0
025 D000006 0
025 D000007 0
025 D000008 0
055 A000000 N
055 B000000 N
056 000000 Y
057 000000 N
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 22.1
<PAGE> PAGE 3
062 J000000 0.0
062 K000000 0.0
062 L000000 0.0
062 M000000 0.0
062 N000000 0.0
062 O000000 0.0
062 P000000 36.0
062 Q000000 0.0
062 R000000 41.0
063 A000000 0
063 B000000 4.4
066 A000000 N
067 000000 N
068 A000000 N
068 B000000 N
069 000000 N
071 A000000 11261
071 B000000 22251
071 C000000 53221
071 D000000 21
072 A000000 6
072 B000000 1221
072 C000000 681
072 D000000 0
072 E000000 0
072 F000000 240
072 G000000 0
072 H000000 0
072 I000000 9
072 J000000 7
072 K000000 0
072 L000000 26
072 M000000 20
072 N000000 0
072 O000000 7
072 P000000 0
072 Q000000 9
072 R000000 11
072 S000000 1
072 T000000 0
072 U000000 0
072 V000000 0
072 W000000 0
072 X000000 330
072 Y000000 0
072 Z000000 1572
072AA000000 3313
072BB000000 1255
072CC010000 0
072CC020000 350
072DD010000 1855
<PAGE> PAGE 4
072DD020000 0
072EE000000 5143
073 A010000 0.8300
073 A020000 0.0000
073 B000000 2.3000
073 C000000 0.0000
074 A000000 45
074 B000000 0
074 C000000 13998
074 D000000 22900
074 E000000 18293
074 F000000 7743
074 G000000 0
074 H000000 0
074 I000000 0
074 J000000 441
074 K000000 0
074 L000000 388
074 M000000 11
074 N000000 63819
074 O000000 213
074 P000000 40
074 Q000000 0
074 R010000 0
074 R020000 0
074 R030000 0
074 R040000 32
074 S000000 0
074 T000000 63534
074 U010000 2236
074 U020000 0
074 V010000 28.41
074 V020000 0.00
074 W000000 0.0000
074 X000000 1046
074 Y000000 0
075 A000000 0
075 B000000 64463
076 000000 25.44
077 A000000 Y
077 B000000 N
077 C000000 Y
077 D000000 N
077 E000000 N
077 F000000 N
077 G000000 N
077 H000000 N
077 I000000 N
077 J000000 N
077 K000000 N
077 L000000 N
<PAGE> PAGE 5
077 M000000 N
077 N000000 N
077 O000000 N
077 P000000 N
077 Q010000 Y
077 Q020000 N
077 Q030000 N
078 000000 N
080 C000000 0
081 B000000 0
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 16
086 A020000 386
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
SIGNATURE GREGORY S. DUCH
TITLE TREASURER
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000018180
<NAME> CASTLE CONVERTIBLE FUND INC
<MULTIPLIER> 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> OCT-31-1998
<PERIOD-END> APR-30-1998
<INVESTMENTS-AT-COST> 56107623
<INVESTMENTS-AT-VALUE> 62934014
<RECEIVABLES> 828564
<ASSETS-OTHER> 56554
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 63819132
<PAYABLE-FOR-SECURITIES> 212604
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 72640
<TOTAL-LIABILITIES> 285244
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 54012068
<SHARES-COMMON-STOCK> 2236003
<SHARES-COMMON-PRIOR> 2236003
<ACCUMULATED-NII-CURRENT> 351914
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 2343515
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 6826391
<NET-ASSETS> 63533888
<DIVIDEND-INCOME> 680647
<INTEREST-INCOME> 1221233
<OTHER-INCOME> 0
<EXPENSES-NET> 329787
<NET-INVESTMENT-INCOME> 1572093
<REALIZED-GAINS-CURRENT> 2057756
<APPREC-INCREASE-CURRENT> (349587)
<NET-CHANGE-FROM-OPS> 3280262
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 1855823
<DISTRIBUTIONS-OF-GAINS> 5142806
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> (3718367)
<ACCUMULATED-NII-PRIOR> 635644
<ACCUMULATED-GAINS-PRIOR> 5428565
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 239750
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 329787
<AVERAGE-NET-ASSETS> 64463031
<PER-SHARE-NAV-BEGIN> 30.08
<PER-SHARE-NII> .71
<PER-SHARE-GAIN-APPREC> .75
<PER-SHARE-DIVIDEND> .83
<PER-SHARE-DISTRIBUTIONS> 2.30
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 28.41
<EXPENSE-RATIO> 1.03
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>