<PAGE> PAGE 1
000 A000000 06/30/98
000 C000000 0000725919
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0.a
000 J000000 A
001 A000000 ALLIANCE MORTGAGE SECURITIES INCOME FUND, INC
001 B000000 811-03829
001 C000000 2013194104
002 A000000 500 PLAZA DRIVE
002 B000000 SECAUCUS
002 C000000 NJ
002 D010000 07094
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 ALLIANCE CAPITAL MANAGEMENT L.P.
008 B000001 A
008 C000001 801-32361
008 D010001 NEW YORK
008 D020001 NY
008 D030001 10105
011 A000001 ALLIANCE FUND DISTRIBUTORS, INC.
011 B000001 8-30851
011 C010001 NEW YORK
011 C020001 NY
011 C030001 10105
012 A000001 ALLIANCE FUND SERVICES, INC.
012 B000001 84-0001187
012 C010001 SECAUCUS
012 C020001 NJ
012 C030001 07096
013 A000001 ERNST & YOUNG LLP
013 B010001 NEW YORK
013 B020001 NY
<PAGE> PAGE 2
013 B030001 10019
014 A000001 DONALDSON, LUFKIN & JENRETTE SECURITIES CORP.
014 B000001 8-00017574
015 A000001 STATE STREET BANK AND TRUST CO.
015 B000001 C
015 C010001 BOSTON
015 C020001 MA
015 C030001 02110
015 E010001 X
018 000000 Y
019 A000000 Y
019 B000000 53
019 C000000 ALLIANCECA
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 PAINE WEBBER INC.
022 B000001 13-2638166
022 C000001 688357
022 D000001 179608
022 A000002 UBS SECURITIES INC.
022 B000002 13-2932996
022 C000002 409735
022 D000002 0
022 A000003 PRUDENTIAL SECURITIES INC.
022 B000003 22-2347336
022 C000003 369162
022 D000003 31113
022 A000004 LEHMAN BROTHERS INC.
022 B000004 13-2518466
022 C000004 174472
022 D000004 150229
022 A000005 SALOMON SMITH BARNEY INC.
022 B000005 13-1912900
022 C000005 111506
022 D000005 108804
022 A000006 GREENWICH SECURITIES, INC.
022 B000006 13-2697091
022 C000006 80543
022 D000006 104184
022 A000007 STATE STREET BANK AND TRUST CO.
022 B000007 04-1867445
022 C000007 167446
<PAGE> PAGE 3
022 D000007 0
022 A000008 GOLDMAN SACHS & CO.
022 B000008 13-5108880
022 C000008 60698
022 D000008 7206
022 A000009 NOMURA SECURITIES INTERNATIONAL INC.
022 B000009 13-2642206
022 C000009 50941
022 D000009 0
022 A000010 CHASE SECURITIES, INC.
022 B000010 13-3112953
022 C000010 0
022 D000010 46527
023 C000000 2152963
023 D000000 696291
024 000000 Y
025 A000001 MERRILL LYNCH PIERCE FENNER & SMITH
025 B000001 13-5674085
025 C000001 D
025 D000001 14401
025 D000002 0
025 D000003 0
025 D000004 0
025 D000005 0
025 D000006 0
025 D000007 0
025 D000008 0
026 A000000 N
026 B000000 N
026 C000000 N
026 D000000 N
026 E000000 N
026 F000000 N
026 G010000 N
026 G020000 N
026 H000000 N
027 000000 Y
028 A010000 3319
028 A020000 1970
028 A030000 0
028 A040000 15821
028 B010000 2964
028 B020000 1931
028 B030000 0
028 B040000 18555
028 C010000 9794
028 C020000 1905
028 C030000 0
028 C040000 24093
028 D010000 9141
028 D020000 1878
<PAGE> PAGE 4
028 D030000 0
028 D040000 24419
028 E010000 9839
028 E020000 1847
028 E030000 0
028 E040000 18897
028 F010000 19351
028 F020000 2151
028 F030000 0
028 F040000 31721
028 G010000 54408
028 G020000 11682
028 G030000 0
028 G040000 133506
028 H000000 7862
029 000000 Y
030 A000000 162
030 B000000 4.25
030 C000000 4.25
031 A000000 0
031 B000000 0
032 000000 162
033 000000 0
034 000000 Y
035 000000 36
036 A000000 Y
036 B000000 0
037 000000 N
038 000000 0
039 000000 N
040 000000 Y
041 000000 Y
042 A000000 0
042 B000000 0
042 C000000 100
042 D000000 0
042 E000000 0
042 F000000 0
042 G000000 0
042 H000000 0
043 000000 2154
044 000000 0
045 000000 Y
046 000000 N
047 000000 Y
048 000000 0.000
048 A010000 500000
048 A020000 0.550
048 B010000 0
048 B020000 0.000
048 C010000 0
<PAGE> PAGE 5
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 500000
048 K020000 0.500
049 000000 N
050 000000 N
051 000000 N
052 000000 N
053 A000000 N
054 A000000 Y
054 B000000 Y
054 C000000 N
054 D000000 N
054 E000000 N
054 F000000 N
054 G000000 Y
054 H000000 Y
054 I000000 N
054 J000000 Y
054 K000000 N
054 L000000 N
054 M000000 Y
054 N000000 N
054 O000000 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 250
062 A000000 Y
062 B000000 0.0
062 C000000 0.0
062 D000000 0.1
062 E000000 0.0
<PAGE> PAGE 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 4.8
062 N000000 100.9
062 O000000 0.0
062 P000000 0.0
062 Q000000 12.5
062 R000000 0.0
063 A000000 0
063 B000000 0.0
064 A000000 N
064 B000000 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 N
070 F010000 N
070 F020000 N
070 G010000 N
070 G020000 N
070 H010000 N
070 H020000 N
070 I010000 N
070 I020000 N
070 J010000 Y
070 J020000 N
070 K010000 N
070 K020000 N
070 L010000 N
070 L020000 N
070 M010000 N
070 M020000 N
070 N010000 Y
070 N020000 Y
070 O010000 Y
<PAGE> PAGE 7
070 O020000 N
070 P010000 N
070 P020000 N
070 Q010000 N
070 Q020000 N
070 R010000 N
070 R020000 N
071 A000000 832877
071 B000000 699025
071 C000000 816916
071 D000000 86
072 A000000 6
072 B000000 27613
072 C000000 0
072 D000000 0
072 E000000 0
072 F000000 1805
072 G000000 75
072 H000000 0
072 I000000 585
072 J000000 134
072 K000000 0
072 L000000 65
072 M000000 12
072 N000000 28
072 O000000 14
072 P000000 2686
072 Q000000 0
072 R000000 38
072 S000000 9
072 T000000 2154
072 U000000 0
072 V000000 0
072 W000000 10
072 X000000 7615
072 Y000000 0
072 Z000000 19998
072AA000000 3469
072BB000000 0
072CC010000 0
072CC020000 1869
072DD010000 11976
072DD020000 9417
072EE000000 0
073 A010000 0.2800
073 A020000 0.2500
073 B000000 0.0000
073 C000000 0.0000
074 A000000 0
074 B000000 700
074 C000000 0
<PAGE> PAGE 8
074 D000000 776489
074 E000000 0
074 F000000 0
074 G000000 0
074 H000000 0
074 I000000 0
074 J000000 50987
074 K000000 0
074 L000000 7567
074 M000000 26
074 N000000 835769
074 O000000 25600
074 P000000 1031
074 Q000000 0
074 R010000 149853
074 R020000 0
074 R030000 0
074 R040000 2228
074 S000000 0
074 T000000 657057
074 U010000 42573
074 U020000 33593
074 V010000 8.63
074 V020000 8.63
074 W000000 0.0000
074 X000000 33247
074 Y000000 0
075 A000000 0
075 B000000 690083
076 000000 0.00
077 A000000 N
078 000000 N
080 A000000 ICI MUTUAL INSURANCE CO.
080 B000000 GULF INSURANCE COMPANY
080 C000000 92000
081 A000000 Y
081 B000000 105
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
<PAGE> PAGE 9
086 D010000 0
086 D020000 0
086 E010000 0
086 E020000 0
086 F010000 0
086 F020000 0
SIGNATURE BETH SMITH
TITLE ASST. VICE PRESIDENT
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000725919
<NAME> ALLIANCE MORTGAGE SECURITIES INCOME FUND, INC.
<SERIES>
<NUMBER> 001
<NAME> ALLIANCE MORTGAGE SECURITIES INCOME FUND, INC.
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-START> JAN-01-1998
<PERIOD-END> JUN-30-1998
<INVESTMENTS-AT-COST> 770,971,666
<INVESTMENTS-AT-VALUE> 777,188,960
<RECEIVABLES> 58,554,380
<ASSETS-OTHER> 25,789
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 835,769,129
<PAYABLE-FOR-SECURITIES> 25,600,174
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 153,111,656
<TOTAL-LIABILITIES> 178,711,830
<SENIOR-EQUITY> 761,662
<PAID-IN-CAPITAL-COMMON> 845,516,737
<SHARES-COMMON-STOCK> 42,573,151
<SHARES-COMMON-PRIOR> 43,186,349
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> (2,725,852)
<ACCUMULATED-NET-GAINS> (192,712,542)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 6,217,294
<NET-ASSETS> 657,057,299
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 27,612,705
<OTHER-INCOME> 0
<EXPENSES-NET> (7,614,610)
<NET-INVESTMENT-INCOME> 19,998,095
<REALIZED-GAINS-CURRENT> 3,468,655
<APPREC-INCREASE-CURRENT> (1,868,824)
<NET-CHANGE-FROM-OPS> 21,597,926
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (11,976,420)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 5,602,942
<NUMBER-OF-SHARES-REDEEMED> (6,991,737)
<SHARES-REINVESTED> 775,597
<NET-CHANGE-IN-ASSETS> (67,211,382)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (196,181,197)
<OVERDISTRIB-NII-PRIOR> (1,330,579)
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,805,000
<INTEREST-EXPENSE> 2,686,000
<GROSS-EXPENSE> 4,929,000
<AVERAGE-NET-ASSETS> 365,741,378
<PER-SHARE-NAV-BEGIN> 8.63
<PER-SHARE-NII> 0.26
<PER-SHARE-GAIN-APPREC> 0.02
<PER-SHARE-DIVIDEND> (0.28)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 8.63
<EXPENSE-RATIO> 1.90
<AVG-DEBT-OUTSTANDING> 110,268,000
<AVG-DEBT-PER-SHARE> 1.38
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000725919
<NAME> ALLIANCE MORTGAGE SECURITIES INCOME FUND, INC.
<SERIES>
<NUMBER> 002
<NAME> ALLIANCE MORTGAGE SECURITIES INCOME FUND, INC.
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-START> JAN-01-1998
<PERIOD-END> JUN-30-1998
<INVESTMENTS-AT-COST> 770,971,666
<INVESTMENTS-AT-VALUE> 777,188,960
<RECEIVABLES> 58,554,380
<ASSETS-OTHER> 25,789
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 835,769,129
<PAYABLE-FOR-SECURITIES> 25,600,174
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 153,111,656
<TOTAL-LIABILITIES> 178,711,830
<SENIOR-EQUITY> 761,662
<PAID-IN-CAPITAL-COMMON> 845,516,737
<SHARES-COMMON-STOCK> 30,574,473
<SHARES-COMMON-PRIOR> 37,552,847
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> (2,725,852)
<ACCUMULATED-NET-GAINS> (192,712,542)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 6,217,294
<NET-ASSETS> 657,057,299
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 27,612,705
<OTHER-INCOME> 0
<EXPENSES-NET> (7,614,610)
<NET-INVESTMENT-INCOME> 19,998,095
<REALIZED-GAINS-CURRENT> 3,468,655
<APPREC-INCREASE-CURRENT> (1,868,824)
<NET-CHANGE-FROM-OPS> 21,597,926
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (8,644,908)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 441,004
<NUMBER-OF-SHARES-REDEEMED> (7,935,040)
<SHARES-REINVESTED> 515,662
<NET-CHANGE-IN-ASSETS> (67,211,382)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (196,181,197)
<OVERDISTRIB-NII-PRIOR> (1,330,579)
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,805,000
<INTEREST-EXPENSE> 2,686,000
<GROSS-EXPENSE> 4,929,000
<AVERAGE-NET-ASSETS> 298,064,748
<PER-SHARE-NAV-BEGIN> 8.63
<PER-SHARE-NII> 0.23
<PER-SHARE-GAIN-APPREC> 0.02
<PER-SHARE-DIVIDEND> (0.25)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 8.63
<EXPENSE-RATIO> 2.59
<AVG-DEBT-OUTSTANDING> 110,268,000
<AVG-DEBT-PER-SHARE> 1.38
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000725919
<NAME> ALLIANCE MORTGAGE SECURITIES INCOME FUND, INC.
<SERIES>
<NUMBER> 003
<NAME> ALLIANCE MORTGAGE SECURITIES INCOME FUND, INC.
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-START> JAN-01-1998
<PERIOD-END> JUN-30-1998
<INVESTMENTS-AT-COST> 770,971,666
<INVESTMENTS-AT-VALUE> 777,188,960
<RECEIVABLES> 58,554,380
<ASSETS-OTHER> 25,789
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 835,769,129
<PAYABLE-FOR-SECURITIES> 25,600,174
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 153,111,656
<TOTAL-LIABILITIES> 178,711,830
<SENIOR-EQUITY> 761,662
<PAID-IN-CAPITAL-COMMON> 845,516,737
<SHARES-COMMON-STOCK> 3,018,578
<SHARES-COMMON-PRIOR> 3,229,819
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> (2,725,852)
<ACCUMULATED-NET-GAINS> (192,712,542)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 6,217,294
<NET-ASSETS> 657,057,299
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 27,612,705
<OTHER-INCOME> 0
<EXPENSES-NET> (7,614,610)
<NET-INVESTMENT-INCOME> 19,998,095
<REALIZED-GAINS-CURRENT> 3,468,655
<APPREC-INCREASE-CURRENT> (1,868,824)
<NET-CHANGE-FROM-OPS> 21,597,926
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (772,040)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 256,481
<NUMBER-OF-SHARES-REDEEMED> (528,639)
<SHARES-REINVESTED> 60,917
<NET-CHANGE-IN-ASSETS> (67,211,382)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (196,181,197)
<OVERDISTRIB-NII-PRIOR> (1,330,579)
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,805,000
<INTEREST-EXPENSE> 2,686,000
<GROSS-EXPENSE> 4,929,000
<AVERAGE-NET-ASSETS> 26,589,794
<PER-SHARE-NAV-BEGIN> 8.63
<PER-SHARE-NII> 0.23
<PER-SHARE-GAIN-APPREC> 0.02
<PER-SHARE-DIVIDEND> (0.25)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 8.63
<EXPENSE-RATIO> 2.59
<AVG-DEBT-OUTSTANDING> 110,268,000
<AVG-DEBT-PER-SHARE> 1.38
</TABLE>