<PAGE> PAGE 1
000 B000000 12/31/98
000 C000000 0000779128
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 100% U.S. TREASURY MONEY MARKET FUND
001 B000000 811-4430
001 C000000 2129226822
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 163
019 C000000 DREYFUSFAM
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 UBS AG
022 B000001 13-2932996
022 C000001 1606683
022 D000001 888233
022 A000002 DONALDSON, LUFKIN & JENRETTE SECURITIES CORP.
022 B000002 13-2741729
022 C000002 1680802
022 D000002 794542
<PAGE> PAGE 2
022 A000003 ABN AMRO SECURITIES (USA) INC.
022 B000003 13-3227945
022 C000003 309391
022 D000003 113270
022 A000004 NIKKO SECURITIES CO. INTERNATIONAL, INC.(THE)
022 B000004 94-1302123
022 C000004 341337
022 D000004 25010
022 A000005 HSBC JAMES CAPEL SECURITIES, INC.
022 B000005 13-2650272
022 C000005 349630
022 D000005 0
022 A000006 ROBERT W. BAIRD & CO. INCORPORATED
022 B000006 39-6037917
022 C000006 299578
022 D000006 0
022 A000007 GOLDMAN, SACHS & CO.
022 B000007 13-5108880
022 C000007 91891
022 D000007 125138
022 A000008 AUBREY G. LANSTON & CO. INC.
022 B000008 13-5552129
022 C000008 175229
022 D000008 0
022 A000009 BARCLAYS DE ZOETE WEDD SECURITIES, INC.
022 B000009 13-3551367
022 C000009 52803
022 D000009 95342
022 A000010 PRUDENTIAL SECURITIES INCORPORATED
022 B000010 22-2347336
022 C000010 119427
022 D000010 0
023 C000000 5202105
023 D000000 2041536
024 000000 Y
025 A000001 UBS AG
025 B000001 13-2932996
025 C000001 E
025 D000001 499
025 D000002 0
025 D000003 0
025 D000004 0
025 D000005 0
025 D000006 0
025 D000007 0
025 D000008 0
028 A010000 84819
028 A020000 3975
028 A030000 0
028 A040000 88095
028 B010000 78406
<PAGE> PAGE 3
028 B020000 4038
028 B030000 0
028 B040000 58491
028 C010000 82161
028 C020000 3963
028 C030000 0
028 C040000 88497
028 D010000 69465
028 D020000 3724
028 D030000 0
028 D040000 62026
028 E010000 54937
028 E020000 3567
028 E030000 0
028 E040000 67236
028 F010000 122393
028 F020000 3613
028 F030000 0
028 F040000 94567
028 G010000 492181
028 G020000 22883
028 G030000 0
028 G040000 458912
028 H000000 0
029 000000 N
030 A000000 0
030 B000000 0.00
030 C000000 0.00
055 A000000 Y
055 B000000 N
056 000000 N
057 000000 N
062 A000000 Y
062 B000000 98.0
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 0.0
062 L000000 0.0
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 78
<PAGE> PAGE 4
063 B000000 0.0
064 A000000 N
070 A010000 Y
070 A020000 N
070 B010000 Y
070 B020000 N
070 C010000 Y
070 C020000 N
070 D010000 Y
070 D020000 N
070 E010000 Y
070 E020000 N
070 F010000 Y
070 F020000 N
070 G010000 Y
070 G020000 N
070 H010000 Y
070 H020000 N
070 I010000 Y
070 I020000 N
070 J010000 Y
070 J020000 N
070 K010000 Y
070 K020000 N
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 Y
070 R020000 N
071 A000000 0
071 B000000 0
071 C000000 0
071 D000000 0
072 A000000 12
072 B000000 58042
072 C000000 0
072 D000000 0
072 E000000 0
072 F000000 5565
072 G000000 0
072 H000000 0
072 I000000 2466
<PAGE> PAGE 5
072 J000000 81
072 K000000 0
072 L000000 57
072 M000000 67
072 N000000 62
072 O000000 0
072 P000000 0
072 Q000000 0
072 R000000 22
072 S000000 12
072 T000000 0
072 U000000 0
072 V000000 8
072 W000000 16
072 X000000 8357
072 Y000000 0
072 Z000000 49685
072AA000000 105
072BB000000 258
072CC010000 0
072CC020000 0
072DD010000 49685
072DD020000 0
072EE000000 0
073 A010000 0.0446
073 A020000 0.0000
073 B000000 0.0000
073 C000000 0.0000
074 A000000 7568
074 B000000 0
074 C000000 1119873
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 15881
074 M000000 93
074 N000000 1143415
074 O000000 0
074 P000000 531
074 Q000000 0
074 R010000 0
074 R020000 0
074 R030000 0
074 R040000 301
074 S000000 0
074 T000000 1142583
<PAGE> PAGE 6
074 U010000 1142640
074 U020000 0
074 V010000 1.00
074 V020000 0.00
074 W000000 1.0004
074 X000000 25087
074 Y000000 0
075 A000000 1112976
075 B000000 0
076 000000 0.00
077 A000000 Y
077 B000000 Y
080 A000000 VIGILANTE INSURANCE COMPANY
080 B000000 NATIONAL UNION FIRE INSURANCE
080 C000000 125
081 A000000 Y
081 B000000 182
082 A000000 N
082 B000000 0
083 A000000 N
083 B000000 0
084 A000000 N
084 B000000 0
085 A000000 Y
085 B000000 N
SIGNATURE MICHAEL S. PETRUCELLI
TITLE ASSISTANT TREASURER
WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000779128
<NAME> DREYFUS 100% U.S. TREASURY MONEY MARKET FUND
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> YEAR
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 1119873
<INVESTMENTS-AT-VALUE> 1119873
<RECEIVABLES> 15881
<ASSETS-OTHER> 7661
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 1143415
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 832
<TOTAL-LIABILITIES> 832
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 1142929
<SHARES-COMMON-STOCK> 1142640
<SHARES-COMMON-PRIOR> 1203852
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (346)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 0
<NET-ASSETS> 1142583
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 58042
<OTHER-INCOME> 0
<EXPENSES-NET> 8357
<NET-INVESTMENT-INCOME> 49685
<REALIZED-GAINS-CURRENT> (153)
<APPREC-INCREASE-CURRENT> 0
<NET-CHANGE-FROM-OPS> 49532
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (49685)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 1045849
<NUMBER-OF-SHARES-REDEEMED> (1154201)
<SHARES-REINVESTED> 47140
<NET-CHANGE-IN-ASSETS> (61365)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (192)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5565
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 8357
<AVERAGE-NET-ASSETS> 1112976
<PER-SHARE-NAV-BEGIN> 1.00
<PER-SHARE-NII> .045
<PER-SHARE-GAIN-APPREC> .00
<PER-SHARE-DIVIDEND> (.045)
<PER-SHARE-DISTRIBUTIONS> .00
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 1.00
<EXPENSE-RATIO> .008
<AVG-DEBT-OUTSTANDING> .000
<AVG-DEBT-PER-SHARE> .000
</TABLE>