<PAGE> PAGE 1
000 A000000 02/29/2000
000 C000000 0000276516
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 6.1
000 J000000 A
001 A000000 FIDELITY MONEY MARKET TRUST
001 B000000 811-2861
001 C000000 6037917488
002 A000000 82 DEVONSHIRE STREET
002 B000000 BOSTON
002 C000000 MA
002 D010000 02109
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 Y
007 B000000 2
007 C010100 1
007 C010200 2
007 C010300 3
007 C010400 4
007 C020400 RETIREMENT MONEY MARKET PORTFOLIO
007 C030400 N
007 C010500 5
007 C020500 RETIREMENT GOVERNMENT MONEY MARKET PORTFOLIO
007 C030500 N
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
008 A00AA01 FIDELITY MANAGEMENT & RESEARCH COMPANY
008 B00AA01 A
008 C00AA01 801-7884
008 D01AA01 BOSTON
008 D02AA01 MA
008 D03AA01 02109
008 A00AA02 FIDELITY INVESTMENTS MONEY MANAGEMENT, INC.
008 B00AA02 S
008 C00AA02 801-34590
008 D01AA02 MERRIMACK
008 D02AA02 NH
008 D03AA02 03054
011 A00AA01 FIDELITY DISTRIBUTORS CORPORATION
011 B00AA01 8-8775
011 C01AA01 BOSTON
<PAGE> PAGE 2
011 C02AA01 MA
011 C03AA01 02109
012 A00AA01 FIDELITY INVESTMENTS INSTIT. OPER. CO., INC.
012 B00AA01 84-1839
012 C01AA01 BOSTON
012 C02AA01 MA
012 C03AA01 02109
013 A00AA01 PRICEWATERHOUSECOOPERS LLP
013 B01AA01 BOSTON
013 B02AA01 MA
013 B03AA01 02109
014 A00AA01 FIDELITY DISTRIBUTORS CORPORATION
014 B00AA01 8-8775
014 A00AA02 FIDELITY BROKERAGE SERVICES
014 B00AA02 8-23292
014 A00AA03 NATIONAL FINANCIAL SERVICES CORP.
014 B00AA03 8-26740
014 A00AA04 DELETE
015 A00AA01 THE BANK OF NEW YORK
015 B00AA01 C
015 C01AA01 NEW YORK
015 C02AA01 NY
015 C03AA01 10260
015 E01AA01 X
018 00AA00 Y
019 A00AA00 Y
019 B00AA00 235
019 C00AA00 FIDELITYZZ
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 GOLDMAN SACHS & CO.
022 B000001 13-5108880
022 C000001 3835467
022 D000001 546943
022 A000002 J.P. MORGAN SECURITES, INC.
022 B000002 13-3224016
022 C000002 3002411
022 D000002 388374
022 A000003 MERRILL LYNCH, PIERCE, FENNER & SMITH, INC.
022 B000003 13-5674085
022 C000003 2210749
022 D000003 520542
<PAGE> PAGE 3
022 A000004 LEHMAN BROTHERS, INC.
022 B000004 13-2518466
022 C000004 2113462
022 D000004 542340
022 A000005 MORGAN STANLEY & CO., INC.
022 B000005 13-2655998
022 C000005 2124037
022 D000005 482501
022 A000006 CREDIT SUISSE FIRST BOSTON
022 B000006 13-5659485
022 C000006 1355625
022 D000006 697901
022 A000007 SALOMON SMITH BARNEY, INC.
022 B000007 13-1912900
022 C000007 1837236
022 D000007 178561
022 A000008 CHASE SECURITIES
022 B000008 13-3112953
022 C000008 1409287
022 D000008 114872
022 A000009 WESTDEUTSCHE LANDESBANK GIROZENTRALE
022 B000009 00-0000000
022 C000009 1388529
022 D000009 0
022 A000010 GENERAL ELECTRIC CREDIT
022 B000010 06-1362678
022 C000010 1018642
022 D000010 187599
023 C000000 123810133
023 D000000 4891109
026 A000000 Y
026 B000000 Y
026 C000000 N
026 D000000 Y
026 E000000 N
026 F000000 Y
026 G010000 N
026 G020000 Y
026 H000000 Y
027 000000 Y
029 00AA00 N
030 A00AA00 0
030 B00AA00 0.00
030 C00AA00 0.00
031 A00AA00 0
031 B00AA00 0
032 00AA00 0
033 00AA00 0
034 00AA00 N
035 00AA00 0
036 B00AA00 0
<PAGE> PAGE 4
037 00AA00 N
038 00AA00 0
039 00AA00 N
040 00AA00 Y
041 00AA00 N
045 00AA00 Y
046 00AA00 N
047 00AA00 Y
048 00AA00 0.420
048 A01AA00 0
048 A02AA00 0.000
048 B01AA00 0
048 B02AA00 0.000
048 C01AA00 0
048 C02AA00 0.000
048 D01AA00 0
048 D02AA00 0.000
048 E01AA00 0
048 E02AA00 0.000
048 F01AA00 0
048 F02AA00 0.000
048 G01AA00 0
048 G02AA00 0.000
048 H01AA00 0
048 H02AA00 0.000
048 I01AA00 0
048 I02AA00 0.000
048 J01AA00 0
048 J02AA00 0.000
048 K01AA00 0
048 K02AA00 0.000
049 00AA00 N
050 00AA00 N
051 00AA00 N
052 00AA00 N
053 A00AA00 Y
053 B00AA00 Y
053 C00AA00 N
054 A00AA00 Y
054 B00AA00 Y
054 C00AA00 Y
054 D00AA00 Y
054 E00AA00 Y
054 F00AA00 Y
054 G00AA00 Y
054 H00AA00 Y
054 I00AA00 N
054 J00AA00 Y
054 K00AA00 Y
054 L00AA00 Y
054 M00AA00 Y
<PAGE> PAGE 5
054 N00AA00 Y
054 O00AA00 Y
055 A00AA00 N
055 B00AA00 N
056 00AA00 Y
057 00AA00 N
058 A00AA00 N
059 00AA00 Y
060 A00AA00 Y
060 B00AA00 Y
061 00AA00 100000
066 A00AA00 N
067 00AA00 N
068 A00AA00 N
068 B00AA00 N
069 00AA00 N
077 A000000 N
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
024 000400 Y
025 A000401 GOLDMAN SACHS & CO.
025 B000401 13-5108880
025 C000401 D
025 D000401 94246
025 A000402 WESTDEUTSCHE LANDESBANK GIROZENTRALE
025 B000402 00-0000000
025 C000402 D
025 D000402 273608
025 A000403 J.P. MORGAN SECURITIES, INC.
025 B000403 13-3224016
025 C000403 D
025 D000403 24946
025 A000404 GENERAL ELECTRIC CAPITAL CORP.
025 B000404 06-1362678
025 C000404 D
025 D000404 573154
025 A000405 LEHMAN BROTHERS, INC.
025 B000405 13-2518466
025 C000405 D
025 D000405 77000
<PAGE> PAGE 6
025 A000406 DELETE
025 D000406 0
025 A000407 DELETE
025 D000407 0
025 D000408 0
025 D000409 0
025 D000410 0
025 D000411 0
025 D000412 0
025 D000413 0
025 D000414 0
025 D000415 0
025 D000416 0
028 A010400 1165892
028 A020400 43202
028 A030400 0
028 A040400 1010844
028 B010400 1471543
028 B020400 47592
028 B030400 0
028 B040400 1148861
028 C010400 2442854
028 C020400 45969
028 C030400 0
028 C040400 3163568
028 D010400 1802619
028 D020400 49303
028 D030400 0
028 D040400 1487974
028 E010400 2044838
028 E020400 49284
028 E030400 0
028 E040400 2282294
028 F010400 1310492
028 F020400 45675
028 F030400 0
028 F040400 1676943
028 G010400 10238238
028 G020400 281025
028 G030400 0
028 G040400 10770484
028 H000400 0
042 A000400 0
042 B000400 0
042 C000400 0
042 D000400 0
042 E000400 0
042 F000400 0
042 G000400 0
042 H000400 0
043 000400 0
<PAGE> PAGE 7
044 000400 15
062 A000400 Y
062 B000400 0.0
062 C000400 0.0
062 D000400 0.6
062 E000400 0.0
062 F000400 3.1
062 G000400 31.7
062 H000400 0.0
062 I000400 43.5
062 J000400 0.5
062 K000400 0.0
062 L000400 20.8
062 M000400 0.0
062 N000400 0.0
062 O000400 0.0
062 P000400 0.0
062 Q000400 0.0
062 R000400 0.0
063 A000400 49
063 B000400 0.0
064 A000400 N
064 B000400 N
070 A010400 Y
070 A020400 Y
070 B010400 N
070 B020400 N
070 C010400 N
070 C020400 N
070 D010400 N
070 D020400 N
070 E010400 N
070 E020400 N
070 F010400 N
070 F020400 N
070 G010400 N
070 G020400 N
070 H010400 N
070 H020400 N
070 I010400 N
070 I020400 N
070 J010400 Y
070 J020400 Y
070 K010400 Y
070 K020400 N
070 L010400 Y
070 L020400 Y
070 M010400 N
070 M020400 N
070 N010400 Y
070 N020400 N
<PAGE> PAGE 8
070 O010400 Y
070 O020400 N
070 P010400 Y
070 P020400 N
070 Q010400 N
070 Q020400 N
070 R010400 Y
070 R020400 N
071 A000400 0
071 B000400 0
071 C000400 0
071 D000400 0
072 A000400 6
072 B000400 301136
072 C000400 0
072 D000400 0
072 E000400 0
072 F000400 21795
072 G000400 0
072 H000400 0
072 I000400 0
072 J000400 0
072 K000400 0
072 L000400 0
072 M000400 17
072 N000400 0
072 O000400 0
072 P000400 0
072 Q000400 0
072 R000400 0
072 S000400 0
072 T000400 0
072 U000400 0
072 V000400 0
072 W000400 0
072 X000400 21812
072 Y000400 1726
072 Z000400 281050
072AA000400 0
072BB000400 103
072CC010400 0
072CC020400 0
072DD010400 281050
072DD020400 0
072EE000400 0
073 A010400 0.0270
073 A020400 0.0000
073 B000400 0.0000
073 C000400 0.0000
074 A000400 0
074 B000400 56358
<PAGE> PAGE 9
074 C000400 10027725
074 D000400 0
074 E000400 0
074 F000400 0
074 G000400 0
074 H000400 0
074 I000400 0
074 J000400 0
074 K000400 0
074 L000400 98914
074 M000400 0
074 N000400 10182997
074 O000400 35254
074 P000400 3421
074 Q000400 0
074 R010400 0
074 R020400 0
074 R030400 0
074 R040400 85171
074 S000400 0
074 T000400 10059151
074 U010400 10059437
074 U020400 0
074 V010400 1.00
074 V020400 0.00
074 W000400 1.0000
074 X000400 1559564
074 Y000400 0
075 A000400 10443186
075 B000400 0
076 000400 0.00
080 A000400 AMERICAN INT'L SPECIALTY LINES INS. CO.
080 B000400 FEDERAL INSURANCE COMPANY
080 C000400 220000
081 A000400 Y
081 B000400 234
082 A000400 N
082 B000400 0
083 A000400 N
083 B000400 0
084 A000400 N
084 B000400 0
085 A000400 Y
085 B000400 N
024 000500 N
025 D000501 0
025 D000502 0
025 D000503 0
025 D000504 0
025 D000505 0
025 D000506 0
<PAGE> PAGE 10
025 D000507 0
025 D000508 0
028 A010500 505942
028 A020500 17127
028 A030500 0
028 A040500 441884
028 B010500 650285
028 B020500 18305
028 B030500 0
028 B040500 504857
028 C010500 573423
028 C020500 18788
028 C030500 0
028 C040500 614144
028 D010500 858053
028 D020500 20276
028 D030500 0
028 D040500 719520
028 E010500 768974
028 E020500 20229
028 E030500 0
028 E040500 951981
028 F010500 715156
028 F020500 18819
028 F030500 0
028 F040500 1064745
028 G010500 4071833
028 G020500 113544
028 G030500 0
028 G040500 4297131
028 H000500 0
042 A000500 0
042 B000500 0
042 C000500 0
042 D000500 0
042 E000500 0
042 F000500 0
042 G000500 0
042 H000500 0
043 000500 0
044 000500 26
062 A000500 Y
062 B000500 0.0
062 C000500 71.1
062 D000500 34.2
062 E000500 0.0
062 F000500 0.0
062 G000500 0.0
062 H000500 0.0
062 I000500 0.0
062 J000500 0.0
<PAGE> PAGE 11
062 K000500 0.0
062 L000500 0.0
062 M000500 0.0
062 N000500 0.0
062 O000500 0.0
062 P000500 0.0
062 Q000500 0.0
062 R000500 0.0
063 A000500 56
063 B000500 0.0
064 A000500 Y
064 B000500 N
070 A010500 Y
070 A020500 Y
070 B010500 N
070 B020500 N
070 C010500 N
070 C020500 N
070 D010500 N
070 D020500 N
070 E010500 N
070 E020500 N
070 F010500 N
070 F020500 N
070 G010500 N
070 G020500 N
070 H010500 N
070 H020500 N
070 I010500 N
070 I020500 N
070 J010500 Y
070 J020500 N
070 K010500 Y
070 K020500 N
070 L010500 N
070 L020500 N
070 M010500 N
070 M020500 N
070 N010500 Y
070 N020500 N
070 O010500 Y
070 O020500 N
070 P010500 Y
070 P020500 N
070 Q010500 N
070 Q020500 N
070 R010500 Y
070 R020500 N
071 A000500 0
071 B000500 0
071 C000500 0
<PAGE> PAGE 12
071 D000500 0
072 A000500 6
072 B000500 122313
072 C000500 0
072 D000500 0
072 E000500 0
072 F000500 9142
072 G000500 0
072 H000500 0
072 I000500 0
072 J000500 0
072 K000500 0
072 L000500 0
072 M000500 7
072 N000500 0
072 O000500 0
072 P000500 5
072 Q000500 0
072 R000500 0
072 S000500 0
072 T000500 0
072 U000500 0
072 V000500 0
072 W000500 0
072 X000500 9154
072 Y000500 624
072 Z000500 113783
072AA000500 102
072BB000500 0
072CC010500 0
072CC020500 0
072DD010500 113783
072DD020500 0
072EE000500 0
073 A010500 0.0260
073 A020500 0.0000
073 B000500 0.0000
073 C000500 0.0000
074 A000500 0
074 B000500 1397517
074 C000500 2904561
074 D000500 0
074 E000500 0
074 F000500 0
074 G000500 0
074 H000500 0
074 I000500 0
074 J000500 0
074 K000500 0
074 L000500 41835
074 M000500 0
<PAGE> PAGE 13
074 N000500 4343913
074 O000500 29997
074 P000500 1456
074 Q000500 0
074 R010500 0
074 R020500 0
074 R030500 0
074 R040500 225187
074 S000500 0
074 T000500 4087273
074 U010500 4087329
074 U020500 0
074 V010500 1.00
074 V020500 0.00
074 W000500 1.0000
074 X000500 714160
074 Y000500 0
075 A000500 4380143
075 B000500 0
076 000500 0.00
080 A000500 AMERICAN INT'L SPECIALTY LINES INS. CO.
080 B000500 FEDERAL INSURANCE COMPANY
080 C000500 220000
081 A000500 Y
081 B000500 234
082 A000500 N
082 B000500 0
083 A000500 N
083 B000500 0
084 A000500 N
084 B000500 0
085 A000500 Y
085 B000500 N
SIGNATURE JOHN H. COSTELLO
TITLE ASSISTANT TREASURER
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000276516
<NAME> Fidelity Money Market Trust
<SERIES>
<NUMBER> 41
<NAME> Retirement Money Market Portfolio
<MULTIPLIER> 1,000
<S>
<C>
<PERIOD-TYPE>
6-mos
<FISCAL-YEAR-END>
aug-31-2000
<PERIOD-END>
feb-29-2000
<INVESTMENTS-AT-COST>
10,084,083
<INVESTMENTS-AT-VALUE>
10,084,083
<RECEIVABLES>
98,914
<ASSETS-OTHER>
0
<OTHER-ITEMS-ASSETS>
0
<TOTAL-ASSETS>
10,182,997
<PAYABLE-FOR-SECURITIES>
35,254
<SENIOR-LONG-TERM-DEBT>
0
<OTHER-ITEMS-LIABILITIES>
88,592
<TOTAL-LIABILITIES>
123,846
<SENIOR-EQUITY>
0
<PAID-IN-CAPITAL-COMMON>
10,059,509
<SHARES-COMMON-STOCK>
10,059,437
<SHARES-COMMON-PRIOR>
10,310,658
<ACCUMULATED-NII-CURRENT>
0
<OVERDISTRIBUTION-NII>
0
<ACCUMULATED-NET-GAINS>
(358)
<OVERDISTRIBUTION-GAINS>
0
<ACCUM-APPREC-OR-DEPREC>
0
<NET-ASSETS>
10,059,151
<DIVIDEND-INCOME>
0
<INTEREST-INCOME>
301,136
<OTHER-INCOME>
0
<EXPENSES-NET>
20,087
<NET-INVESTMENT-INCOME>
281,049
<REALIZED-GAINS-CURRENT>
(102)
<APPREC-INCREASE-CURRENT>
0
<NET-CHANGE-FROM-OPS>
280,947
<EQUALIZATION>
0
<DISTRIBUTIONS-OF-INCOME>
281,049
<DISTRIBUTIONS-OF-GAINS>
0
<DISTRIBUTIONS-OTHER>
0
<NUMBER-OF-SHARES-SOLD>
10,238,238
<NUMBER-OF-SHARES-REDEEMED>
10,770,484
<SHARES-REINVESTED>
281,025
<NET-CHANGE-IN-ASSETS>
(251,324)
<ACCUMULATED-NII-PRIOR>
0
<ACCUMULATED-GAINS-PRIOR>
(255)
<OVERDISTRIB-NII-PRIOR>
0
<OVERDIST-NET-GAINS-PRIOR>
0
<GROSS-ADVISORY-FEES>
21,795
<INTEREST-EXPENSE>
0
<GROSS-EXPENSE>
21,812
<AVERAGE-NET-ASSETS>
10,443,186
<PER-SHARE-NAV-BEGIN>
1.000
<PER-SHARE-NII>
.027
<PER-SHARE-GAIN-APPREC>
0
<PER-SHARE-DIVIDEND>
.027
<PER-SHARE-DISTRIBUTIONS>
0
<RETURNS-OF-CAPITAL>
0
<PER-SHARE-NAV-END>
1.000
<EXPENSE-RATIO>
42
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000276516
<NAME> Fidelity Money Market Trust
<SERIES>
<NUMBER> 51
<NAME> Retirement Government Money Market Portfolio
<MULTIPLIER> 1,000
<S>
<C>
<PERIOD-TYPE>
6-mos
<FISCAL-YEAR-END>
aug-31-2000
<PERIOD-END>
feb-29-2000
<INVESTMENTS-AT-COST>
4,302,078
<INVESTMENTS-AT-VALUE>
4,302,078
<RECEIVABLES>
41,835
<ASSETS-OTHER>
0
<OTHER-ITEMS-ASSETS>
0
<TOTAL-ASSETS>
4,343,913
<PAYABLE-FOR-SECURITIES>
29,997
<SENIOR-LONG-TERM-DEBT>
0
<OTHER-ITEMS-LIABILITIES>
226,643
<TOTAL-LIABILITIES>
256,640
<SENIOR-EQUITY>
0
<PAID-IN-CAPITAL-COMMON>
4,087,427
<SHARES-COMMON-STOCK>
4,087,329
<SHARES-COMMON-PRIOR>
4,199,083
<ACCUMULATED-NII-CURRENT>
0
<OVERDISTRIBUTION-NII>
0
<ACCUMULATED-NET-GAINS>
(154)
<OVERDISTRIBUTION-GAINS>
0
<ACCUM-APPREC-OR-DEPREC>
0
<NET-ASSETS>
4,087,273
<DIVIDEND-INCOME>
0
<INTEREST-INCOME>
122,313
<OTHER-INCOME>
0
<EXPENSES-NET>
8,530
<NET-INVESTMENT-INCOME>
113,783
<REALIZED-GAINS-CURRENT>
103
<APPREC-INCREASE-CURRENT>
0
<NET-CHANGE-FROM-OPS>
113,886
<EQUALIZATION>
0
<DISTRIBUTIONS-OF-INCOME>
113,783
<DISTRIBUTIONS-OF-GAINS>
0
<DISTRIBUTIONS-OTHER>
0
<NUMBER-OF-SHARES-SOLD>
4,071,833
<NUMBER-OF-SHARES-REDEEMED>
4,297,131
<SHARES-REINVESTED>
113,544
<NET-CHANGE-IN-ASSETS>
(111,652)
<ACCUMULATED-NII-PRIOR>
0
<ACCUMULATED-GAINS-PRIOR>
(256)
<OVERDISTRIB-NII-PRIOR>
0
<OVERDIST-NET-GAINS-PRIOR>
0
<GROSS-ADVISORY-FEES>
9,142
<INTEREST-EXPENSE>
5
<GROSS-EXPENSE>
9,154
<AVERAGE-NET-ASSETS>
4,380,143
<PER-SHARE-NAV-BEGIN>
1.000
<PER-SHARE-NII>
.026
<PER-SHARE-GAIN-APPREC>
0
<PER-SHARE-DIVIDEND>
.026
<PER-SHARE-DISTRIBUTIONS>
0
<RETURNS-OF-CAPITAL>
0
<PER-SHARE-NAV-END>
1.000
<EXPENSE-RATIO>
42
</TABLE>
