<PAGE> PAGE 1
000 A000000 09/30/99
000 C000000 0001038520
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0
000 J000000 U
001 A000000 DREYFUS INSTIT. PREFERRED MONEY MARKET FUND
001 B000000 811-8211
001 C000000 2129226806
002 A000000 200 PARK AVENUE
002 B000000 NEW YORK
002 C000000 NY
002 D010000 10166
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 N
007 B000000 0
015 A000001 THE BANK OF NEW YORK
015 B000001 C
015 C010001 NEW YORK
015 C020001 NY
015 C030001 10286
015 E010001 X
018 000000 Y
019 A000000 Y
019 B000000 162
019 C000000 DREYFUSFAM
022 A000001 ASSOCIATES CORPORATION OF NORTH AMERICA
022 B000001 06-0943899
022 C000001 9745994
022 D000001 0
022 A000002 UBS AG
022 B000002 13-2932996
022 C000002 8975303
022 D000002 0
022 A000003 PRUDENTIAL SECURITIES INCORPORATED
022 B000003 22-2347336
022 C000003 7141516
022 D000003 0
022 A000004 BARCLAYS DE ZOETE WEDD SECURITIES, INC.
022 B000004 13-3551367
022 C000004 4479356
022 D000004 0
022 A000005 CHASE SECURITIES, INC.
022 B000005 13-3112953
022 C000005 3703345
<PAGE> PAGE 2
022 D000005 52392
022 A000006 WESTDEUTSCHE LANDESBANK
022 B000006 13-2677075
022 C000006 2855645
022 D000006 0
022 A000007 EURO BROKERS MAXCORE, INC.
022 B000007 12-3410896
022 C000007 2724000
022 D000007 0
022 A000008 BANC ONE CAPITAL CORPORATION
022 B000008 31-1017233
022 C000008 2514253
022 D000008 0
022 A000009 SOCIETE GENERALE SECURITIES CORPORATION
022 B000009 13-1976032
022 C000009 2488110
022 D000009 0
022 A000010 REPUBLIC NATIONAL BANK OF NEW YORK
022 B000010 13-2774727
022 C000010 2222671
022 D000010 0
023 C000000 55604305
023 D000000 141656
024 000000 Y
025 A000001 ASSOCIATES CORPORATION OF NORTH AMERICA
025 B000001 06-0943899
025 C000001 D
025 D000001 100000
025 A000002 PRUDENTIAL SECURITIES INCORPORATED
025 B000002 22-2347336
025 C000002 D
025 D000002 100000
025 A000003 UBS AG
025 B000003 13-2932996
025 C000003 D
025 D000003 100000
025 A000004 SOCIETE GENERALE SECURITIES CORPORAITON
025 B000004 13-1976032
025 C000004 D
025 D000004 24994
025 A000005 DELETE
025 D000005 0
025 D000006 0
025 D000007 0
025 D000008 0
028 A010000 1027349
028 A020000 6209
028 A030000 0
028 A040000 784977
028 B010000 1188020
028 B020000 6848
<PAGE> PAGE 3
028 B030000 0
028 B040000 1259991
028 C010000 1007286
028 C020000 6437
028 C030000 0
028 C040000 1296906
028 D010000 889885
028 D020000 6542
028 D030000 0
028 D040000 818394
028 E010000 1844308
028 E020000 8075
028 E030000 0
028 E040000 930726
028 F010000 1383803
028 F020000 11309
028 F030000 0
028 F040000 1367312
028 G010000 7340651
028 G020000 45420
028 G030000 0
028 G040000 6458306
028 H000000 0
062 A000000 Y
062 B000000 0.0
062 C000000 0.0
062 D000000 0.0
062 E000000 0.0
062 F000000 14.9
062 G000000 15.8
062 H000000 0.0
062 I000000 44.7
062 J000000 4.0
062 K000000 0.0
062 L000000 20.1
062 M000000 0.0
062 N000000 0.0
062 O000000 0.0
062 P000000 0.0
062 Q000000 0.0
062 R000000 0.0
063 A000000 43
063 B000000 0.0
064 A000000 N
064 B000000 N
071 A000000 0
071 B000000 0
071 C000000 0
071 D000000 0
072 A000000 6
072 B000000 54886
<PAGE> PAGE 4
072 C000000 0
072 D000000 0
072 E000000 0
072 F000000 1069
072 G000000 0
072 H000000 0
072 I000000 0
072 J000000 0
072 K000000 0
072 L000000 0
072 M000000 0
072 N000000 0
072 O000000 0
072 P000000 0
072 Q000000 0
072 R000000 0
072 S000000 0
072 T000000 0
072 U000000 0
072 V000000 0
072 W000000 0
072 X000000 1069
072 Y000000 0
072 Z000000 53817
072AA000000 0
072BB000000 15
072CC010000 0
072CC020000 0
072DD010000 53817
072DD020000 0
072EE000000 0
073 A010000 0.0251
073 A020000 0.0000
073 B000000 0.0000
073 C000000 0.0000
074 A000000 0
074 B000000 0
074 C000000 2913945
074 D000000 0
074 E000000 0
074 F000000 0
074 G000000 0
074 H000000 0
074 I000000 0
074 J000000 0
074 K000000 0
074 L000000 16124
074 M000000 0
074 N000000 2930069
074 O000000 0
074 P000000 301
<PAGE> PAGE 5
074 Q000000 0
074 R010000 0
074 R020000 0
074 R030000 0
074 R040000 2612
074 S000000 0
074 T000000 2927156
074 U010000 2927173
074 U020000 0
074 V010000 1.00
074 V020000 0.00
074 W000000 1.0002
074 X000000 36
074 Y000000 0
075 A000000 2137530
075 B000000 0
076 000000 0.00
077 A000000 N
SIGNATURE STEPHANIE D. PIERCE
TITLE VP, ASST.TREASR/SECY
WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0001038520
<NAME> DREYFUS INSTITUTIONAL PREFERRED MONEY MARKET FUND
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> MAR-31-1999
<PERIOD-END> MAR-31-1999
<INVESTMENTS-AT-COST> 1984444
<INVESTMENTS-AT-VALUE> 1984444
<RECEIVABLES> 16420
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 2000864
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 1458
<TOTAL-LIABILITIES> 1458
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 1999408
<SHARES-COMMON-STOCK> 1999408
<SHARES-COMMON-PRIOR> 1496629
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (2)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 0
<NET-ASSETS> 1999406
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 93111
<OTHER-INCOME> 0
<EXPENSES-NET> 1723
<NET-INVESTMENT-INCOME> 91389
<REALIZED-GAINS-CURRENT> 37
<APPREC-INCREASE-CURRENT> 0
<NET-CHANGE-FROM-OPS> 91426
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (91389)
<DISTRIBUTIONS-OF-GAINS> (37)
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 9462363
<NUMBER-OF-SHARES-REDEEMED> (9041452)
<SHARES-REINVESTED> 81867
<NET-CHANGE-IN-ASSETS> 502779
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (3)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1723
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1723
<AVERAGE-NET-ASSETS> 1722572
<PER-SHARE-NAV-BEGIN> 1.00
<PER-SHARE-NII> .05
<PER-SHARE-GAIN-APPREC> .00
<PER-SHARE-DIVIDEND> (.05)
<PER-SHARE-DISTRIBUTIONS> .00
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 1.00
<EXPENSE-RATIO> .001
[AVG-DEBT-OUTSTANDING] 000
[AVG-DEBT-PER-SHARE] 000
</TABLE>