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<PAGE> PAGE 3
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<PAGE> PAGE 6
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<PAGE> PAGE 8
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<PAGE> PAGE 11
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<PAGE> PAGE 12
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<PAGE> PAGE 13
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<PAGE> PAGE 15
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<PAGE> PAGE 16
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<PAGE> PAGE 17
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<PAGE> PAGE 19
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025 D000403 755
025 A000404 MERRILL LYNCH
025 B000404 13-5674085
025 C000404 D
025 D000404 969
025 A000405 MORGAN STANLEY & CO., INC.
025 B000405 13-2655998
025 C000405 D
025 D000405 259
025 D000406 0
<PAGE> PAGE 20
025 D000407 0
025 D000408 0
028 A010400 64206
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<PAGE> PAGE 21
048 I010400 0
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057 000400 Y
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066 A000400 Y
066 G000400 Y
067 000400 Y
068 A000400 N
068 B000400 N
069 000400 N
070 A010400 Y
070 A020400 N
070 B010400 Y
070 B020400 N
070 C010400 Y
070 C020400 N
070 D010400 Y
070 D020400 N
070 E010400 Y
070 E020400 N
070 F010400 Y
070 F020400 N
070 G010400 Y
070 G020400 N
070 H010400 Y
070 H020400 N
070 I010400 N
<PAGE> PAGE 22
070 I020400 N
070 J010400 Y
070 J020400 Y
070 K010400 Y
070 K020400 N
070 L010400 Y
070 L020400 Y
070 M010400 Y
070 M020400 N
070 N010400 Y
070 N020400 Y
070 O010400 Y
070 O020400 N
070 P010400 Y
070 P020400 N
070 Q010400 N
070 Q020400 N
070 R010400 Y
070 R020400 N
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<PAGE> PAGE 23
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076 000400 0.00
008 A000501 MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
008 B000501 A
008 C000501 801-8059
008 D010501 SPRINGFIELD
008 D020501 MA
008 D030501 01111
008 D040501 0001
008 A000502 DAVID L. BABSON AND COMPANY INCORPORATED
008 B000502 S
<PAGE> PAGE 24
008 C000502 801-241
008 D010502 CAMBRIDGE
008 D020502 MA
008 D030502 02142
008 D040502 1300
015 A000501 INVESTORS BANK & TRUST COMPANY
015 B000501 C
015 C010501 BOSTON
015 C020501 MA
015 C030501 02116
015 E010501 X
024 000500 N
028 A010500 59130
028 A020500 0
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028 B010500 89298
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<PAGE> PAGE 25
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055 B000500 N
056 000500 Y
057 000500 Y
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062 F000500 0.0
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066 A000500 Y
066 E000500 Y
067 000500 N
068 A000500 N
068 B000500 N
069 000500 N
070 A010500 Y
070 A020500 N
070 B010500 Y
070 B020500 N
070 C010500 Y
070 C020500 N
070 D010500 Y
<PAGE> PAGE 26
070 D020500 N
070 E010500 Y
070 E020500 N
070 F010500 Y
070 F020500 N
070 G010500 Y
070 G020500 N
070 H010500 Y
070 H020500 N
070 I010500 N
070 I020500 N
070 J010500 Y
070 J020500 N
070 K010500 Y
070 K020500 N
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070 L020500 Y
070 M010500 Y
070 M020500 N
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070 N020500 Y
070 O010500 Y
070 O020500 N
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070 P020500 N
070 Q010500 N
070 Q020500 N
070 R010500 Y
070 R020500 N
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<PAGE> PAGE 27
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072EE000500 202804
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<PAGE> PAGE 28
076 000500 0.00
008 A000601 MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
008 B000601 A
008 C000601 801-8059
008 D010601 SPRINGFIELD
008 D020601 MA
008 D030601 01111
008 D040601 0001
008 A000602 DAVID L. BABSON AND COMPANY INCORPORATED
008 B000602 S
008 C000602 801-241
008 D010602 CAMBRIDGE
008 D020602 MA
008 D030602 02142
008 D040602 1300
015 A000601 INVESTORS BANK & TRUST COMPANY
015 B000601 C
015 C010601 BOSTON
015 C020601 MA
015 C030601 02116
015 E010601 X
024 000600 N
028 A010600 19343
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028 B010600 36855
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<PAGE> PAGE 29
045 000600 Y
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055 A000600 N
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056 000600 Y
057 000600 Y
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066 A000600 Y
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<PAGE> PAGE 30
068 A000600 N
068 B000600 N
069 000600 N
070 A010600 Y
070 A020600 N
070 B010600 Y
070 B020600 N
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070 D020600 N
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070 E020600 N
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070 F020600 N
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070 G020600 N
070 H010600 Y
070 H020600 N
070 I010600 N
070 I020600 N
070 J010600 Y
070 J020600 N
070 K010600 Y
070 K020600 N
070 L010600 Y
070 L020600 N
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070 P020600 N
070 Q010600 N
070 Q020600 N
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070 R020600 N
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<PAGE> PAGE 31
072 I000600 0
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<PAGE> PAGE 32
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008 A000701 MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
008 B000701 A
008 C000701 801-8059
008 D010701 SPRINGFIELD
008 D020701 MA
008 D030701 01111
008 D040701 0001
008 A000702 HARBOURVIEW ASSET MANAGEMENT CORPORATION
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008 D020702 NY
008 D030702 10048
008 D040702 0203
015 A000701 INVESTORS BANK & TRUST COMPANY
015 B000701 C
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015 C030701 02116
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015 A000702 CITIBANK
015 B000702 S
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015 C020702 NY
015 C030702 10043
015 E040702 X
015 A000703 CHASE MANHATTAN BANK
015 B000703 S
015 C010703 NEW YORK
015 C020703 NY
015 C030703 11245
015 E040703 X
015 A000704 NATIONAL AUSTRALIAN BANK
015 B000704 S
015 C010704 MELBOURNE
015 D010704 AUSTRALIA
015 D020704 VICTORIA 3000
015 E040704 X
015 A000705 EUROCLEAR
015 B000705 S
<PAGE> PAGE 33
015 C010705 BRUSSELS
015 D010705 BELGIUM
015 E040705 X
015 A000706 STANDARD CHARTERED BANK
015 B000706 S
015 C010706 LONDON
015 D010706 ENGLAND
015 D020706 EC2V 7SB
015 E040706 X
015 A000707 BANKBOSTON
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015 C020707 MA
015 C030707 02110
015 E040707 X
015 A000708 BANK OF IRELAND
015 B000708 S
015 C010708 DUBLIN
015 D010708 IRELAND
015 D020708 2
015 E040708 X
015 A000709 BANCOMER SA
015 B000709 S
015 C010709 MEXICO CITY
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015 D020709 03339
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015 A000710 BARCLAYS BANK
015 B000710 S
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015 D020710 EC3N 4HJ
015 E040710 X
015 A000711 THE STANDARD BANK OF SOUTH AFRICA LTD
015 B000711 S
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015 A000712 ROYAL TRUST CORPORATION OF CANADA
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024 000700 N
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<PAGE> PAGE 34
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<PAGE> PAGE 35
057 000700 Y
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<PAGE> PAGE 36
070 N010700 Y
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070 R020700 N
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<PAGE> PAGE 37
074 A000700 108
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074 C000700 10196
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074 F000700 599092
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SIGNATURE STEPHEN KUHN
TITLE VICE PRESIDENT
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 031
<NAME> Core Bond Fund, Class A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 750,003,586
<INVESTMENTS-AT-VALUE> 771,338,621
<RECEIVABLES> 10,620,977
<ASSETS-OTHER> 164,850
<OTHER-ITEMS-ASSETS> 0
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<TOTAL-LIABILITIES> 72,123,590
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 688,172,382
<SHARES-COMMON-STOCK> 12,774
<SHARES-COMMON-PRIOR> 12,073
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 493,441
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 21,335,035
<NET-ASSETS> 141,315
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 8,805
<OTHER-INCOME> 0
<EXPENSES-NET> 1,635
<NET-INVESTMENT-INCOME> 7,170
<REALIZED-GAINS-CURRENT> 1,749
<APPREC-INCREASE-CURRENT> 1,225
<NET-CHANGE-FROM-OPS> 10,144
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 6,554
<DISTRIBUTIONS-OF-GAINS> 1,221
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 12,081
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 693
<NET-CHANGE-IN-ASSETS> 10,144
<ACCUMULATED-NII-PRIOR> 1,094,301
<ACCUMULATED-GAINS-PRIOR> 69,810
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 2,419,080
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 2,933,231
<AVERAGE-NET-ASSETS> 136,236
<PER-SHARE-NAV-BEGIN> 10.85
<PER-SHARE-NII> 0.59
<PER-SHARE-GAIN-APPREC> 0.25
<PER-SHARE-DIVIDEND> (0.52)
<PER-SHARE-DISTRIBUTIONS> (0.11)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 11.06
<EXPENSE-RATIO> 1.20
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 032
<NAME> Core Bond Fund, Class Y
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 750,003,586
<INVESTMENTS-AT-VALUE> 771,338,621
<RECEIVABLES> 10,620,977
<ASSETS-OTHER> 164,850
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 782,124,448
<PAYABLE-FOR-SECURITIES> 3,023,136
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 69,100,454
<TOTAL-LIABILITIES> 72,123,590
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 688,172,382
<SHARES-COMMON-STOCK> 36,181
<SHARES-COMMON-PRIOR> 24,644
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 493,441
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 21,335,035
<NET-ASSETS> 400,056
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 19,194
<OTHER-INCOME> 0
<EXPENSES-NET> 2,195
<NET-INVESTMENT-INCOME> 16,999
<REALIZED-GAINS-CURRENT> 3,695
<APPREC-INCREASE-CURRENT> 2,299
<NET-CHANGE-FROM-OPS> 22,993
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 18,553
<DISTRIBUTIONS-OF-GAINS> 3,456
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 34,044
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 2,137
<NET-CHANGE-IN-ASSETS> 131,737
<ACCUMULATED-NII-PRIOR> 1,094,301
<ACCUMULATED-GAINS-PRIOR> 69,810
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 2,419,080
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 2,933,231
<AVERAGE-NET-ASSETS> 296,474
<PER-SHARE-NAV-BEGIN> 10.86
<PER-SHARE-NII> 0.65
<PER-SHARE-GAIN-APPREC> 0.25
<PER-SHARE-DIVIDEND> (0.59)
<PER-SHARE-DISTRIBUTIONS> (0.11)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 11.06
<EXPENSE-RATIO> 0.74
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 033
<NAME> Core Bond Fund, Class S
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 750,003,586
<INVESTMENTS-AT-VALUE> 771,338,621
<RECEIVABLES> 10,620,977
<ASSETS-OTHER> 164,850
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 782,124,448
<PAYABLE-FOR-SECURITIES> 3,023,136
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 69,100,454
<TOTAL-LIABILITIES> 72,123,590
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 688,172,382
<SHARES-COMMON-STOCK> 64,158,721
<SHARES-COMMON-PRIOR> 42,182,957
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 493,441
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 21,335,035
<NET-ASSETS> 709,459,487
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 34,721,686
<OTHER-INCOME> 0
<EXPENSES-NET> 2,929,401
<NET-INVESTMENT-INCOME> 31,792,285
<REALIZED-GAINS-CURRENT> 6,567,709
<APPREC-INCREASE-CURRENT> 4,872,205
<NET-CHANGE-FROM-OPS> 43,232,199
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 32,902,152
<DISTRIBUTIONS-OF-GAINS> 6,128,341
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 38,073,055
<NUMBER-OF-SHARES-REDEEMED> 19,631,777
<SHARES-REINVESTED> 3,534,486
<NET-CHANGE-IN-ASSETS> 253,528,818
<ACCUMULATED-NII-PRIOR> 1,094,301
<ACCUMULATED-GAINS-PRIOR> 69,810
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 2,419,080
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 2,933,231
<AVERAGE-NET-ASSETS> 537,140,709
<PER-SHARE-NAV-BEGIN> 10.81
<PER-SHARE-NII> 0.67
<PER-SHARE-GAIN-APPREC> 0.24
<PER-SHARE-DIVIDEND> (0.56)
<PER-SHARE-DISTRIBUTIONS> (0.10)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 11.06
<EXPENSE-RATIO> 0.55
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 051
<NAME> Core Equity Fund, Class A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 2,264,821,470
<INVESTMENTS-AT-VALUE> 3,675,977,495
<RECEIVABLES> 21,312,151
<ASSETS-OTHER> 3,775
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 3,697,293,421
<PAYABLE-FOR-SECURITIES> 717,456
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 109,417,083
<TOTAL-LIABILITIES> 110,134,539
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 2,154,856,647
<SHARES-COMMON-STOCK> 12,354
<SHARES-COMMON-PRIOR> 11,555
<ACCUMULATED-NII-CURRENT> 106,352
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 21,039,858
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,411,156,025
<NET-ASSETS> 227,342
<DIVIDEND-INCOME> 4,331
<INTEREST-INCOME> 289
<OTHER-INCOME> 0
<EXPENSES-NET> 2,503
<NET-INVESTMENT-INCOME> 2,117
<REALIZED-GAINS-CURRENT> 10,733
<APPREC-INCREASE-CURRENT> 18,480
<NET-CHANGE-FROM-OPS> 31,330
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 4,908
<DISTRIBUTIONS-OF-GAINS> 21,970
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 10,877
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 1,477
<NET-CHANGE-IN-ASSETS> 31,330
<ACCUMULATED-NII-PRIOR> 1,297,337
<ACCUMULATED-GAINS-PRIOR> 49,859,885
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 15,182,885
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 18,192,352
<AVERAGE-NET-ASSETS> 208,747
<PER-SHARE-NAV-BEGIN> 18.02
<PER-SHARE-NII> 0.19
<PER-SHARE-GAIN-APPREC> 2.60
<PER-SHARE-DIVIDEND> (0.43)
<PER-SHARE-DISTRIBUTIONS> (1.98)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 18.40
<EXPENSE-RATIO> 1.20
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 052
<NAME> Core Equity Fund, Class Y
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 2,264,821,470
<INVESTMENTS-AT-VALUE> 3,675,977,495
<RECEIVABLES> 21,312,151
<ASSETS-OTHER> 3,775
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 3,697,293,421
<PAYABLE-FOR-SECURITIES> 717,456
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 109,417,083
<TOTAL-LIABILITIES> 110,134,539
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 2,154,856,647
<SHARES-COMMON-STOCK> 40,993
<SHARES-COMMON-PRIOR> 23,532
<ACCUMULATED-NII-CURRENT> 106,352
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 21,039,858
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,411,156,025
<NET-ASSETS> 754,054
<DIVIDEND-INCOME> 9,173
<INTEREST-INCOME> 613
<OTHER-INCOME> 0
<EXPENSES-NET> 3,365
<NET-INVESTMENT-INCOME> 6,421
<REALIZED-GAINS-CURRENT> 23,715
<APPREC-INCREASE-CURRENT> 45,271
<NET-CHANGE-FROM-OPS> 75,407
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 20,187
<DISTRIBUTIONS-OF-GAINS> 65,959
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 36,358
<NUMBER-OF-SHARES-REDEEMED> 76
<SHARES-REINVESTED> 4,711
<NET-CHANGE-IN-ASSETS> 353,293
<ACCUMULATED-NII-PRIOR> 1,297,337
<ACCUMULATED-GAINS-PRIOR> 49,859,885
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 15,182,885
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 18,192,352
<AVERAGE-NET-ASSETS> 448,015
<PER-SHARE-NAV-BEGIN> 18.03
<PER-SHARE-NII> 0.27
<PER-SHARE-GAIN-APPREC> 2.63
<PER-SHARE-DIVIDEND> (0.56)
<PER-SHARE-DISTRIBUTIONS> (1.98)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 18.39
<EXPENSE-RATIO> 0.75
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 053
<NAME> Core Equity Fund, Class S
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 2,264,821,470
<INVESTMENTS-AT-VALUE> 3,675,977,495
<RECEIVABLES> 21,312,151
<ASSETS-OTHER> 3,775
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 3,697,293,421
<PAYABLE-FOR-SECURITIES> 717,456
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 109,417,083
<TOTAL-LIABILITIES> 110,134,539
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 2,154,856,647
<SHARES-COMMON-STOCK> 194,978,032
<SHARES-COMMON-PRIOR> 188,089,578
<ACCUMULATED-NII-CURRENT> 106,352
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 21,039,858
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,411,156,025
<NET-ASSETS> 3,586,177,486
<DIVIDEND-INCOME> 69,978,916
<INTEREST-INCOME> 4,677,590
<OTHER-INCOME> 0
<EXPENSES-NET> 18,186,484
<NET-INVESTMENT-INCOME> 56,470,022
<REALIZED-GAINS-CURRENT> 173,949,339
<APPREC-INCREASE-CURRENT> 291,674,622
<NET-CHANGE-FROM-OPS> 522,093,983
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 57,644,450
<DISTRIBUTIONS-OF-GAINS> 202,715,885
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 44,529,203
<NUMBER-OF-SHARES-REDEEMED> 52,073,640
<SHARES-REINVESTED> 14,432,891
<NET-CHANGE-IN-ASSETS> 388,329,621
<ACCUMULATED-NII-PRIOR> 1,297,337
<ACCUMULATED-GAINS-PRIOR> 49,859,885
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 15,182,885
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 18,192,352
<AVERAGE-NET-ASSETS> 3,373,317,626
<PER-SHARE-NAV-BEGIN> 17.00
<PER-SHARE-NII> 0.31
<PER-SHARE-GAIN-APPREC> 2.49
<PER-SHARE-DIVIDEND> (0.31)
<PER-SHARE-DISTRIBUTIONS> (1.10)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 18.39
<EXPENSE-RATIO> 0.54
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 011
<NAME> Prime Fund, Class A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 247,916,928
<INVESTMENTS-AT-VALUE> 247,957,829
<RECEIVABLES> 8,305,239
<ASSETS-OTHER> 1,496
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 256,264,564
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,832,071
<TOTAL-LIABILITIES> 3,832,071
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 252,393,164
<SHARES-COMMON-STOCK> 794
<SHARES-COMMON-PRIOR> 758
<ACCUMULATED-NII-CURRENT> 19,112
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (20,684)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 40,901
<NET-ASSETS> 119,698
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 6,757
<OTHER-INCOME> 0
<EXPENSES-NET> 1,404
<NET-INVESTMENT-INCOME> 5,353
<REALIZED-GAINS-CURRENT> (1)
<APPREC-INCREASE-CURRENT> 31
<NET-CHANGE-FROM-OPS> 5,383
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 94,659
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 165
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 629
<NET-CHANGE-IN-ASSETS> 5,383
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (18,160)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,143,154
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,394,367
<AVERAGE-NET-ASSETS> 116,709
<PER-SHARE-NAV-BEGIN> 691.21
<PER-SHARE-NII> 32.03
<PER-SHARE-GAIN-APPREC> (0.09)
<PER-SHARE-DIVIDEND> (572.32)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 150.83
<EXPENSE-RATIO> 1.20
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 012
<NAME> Prime Fund, Class Y
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 247,916,928
<INVESTMENTS-AT-VALUE> 247,957,829
<RECEIVABLES> 8,305,239
<ASSETS-OTHER> 1,496
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 256,264,564
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,832,071
<TOTAL-LIABILITIES> 3,832,071
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 252,393,164
<SHARES-COMMON-STOCK> 3,689
<SHARES-COMMON-PRIOR> 1,547
<ACCUMULATED-NII-CURRENT> 19,112
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (20,684)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 40,901
<NET-ASSETS> 556,080
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 26,541
<OTHER-INCOME> 0
<EXPENSES-NET> 3,308
<NET-INVESTMENT-INCOME> 23,233
<REALIZED-GAINS-CURRENT> 13
<APPREC-INCREASE-CURRENT> (359)
<NET-CHANGE-FROM-OPS> 22,887
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 440,359
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 3,752
<NUMBER-OF-SHARES-REDEEMED> 2,987
<SHARES-REINVESTED> 2,924
<NET-CHANGE-IN-ASSETS> 322,341
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (18,160)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,143,154
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,394,367
<AVERAGE-NET-ASSETS> 445,918
<PER-SHARE-NAV-BEGIN> 690.78
<PER-SHARE-NII> 36.67
<PER-SHARE-GAIN-APPREC> (1.30)
<PER-SHARE-DIVIDEND> (575.42)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 150.73
<EXPENSE-RATIO> 0.74
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 013
<NAME> Prime Fund, Class S
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 247,916,928
<INVESTMENTS-AT-VALUE> 247,957,829
<RECEIVABLES> 8,305,239
<ASSETS-OTHER> 1,496
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 256,264,564
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,832,071
<TOTAL-LIABILITIES> 3,832,071
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 252,393,164
<SHARES-COMMON-STOCK> 1,670,110
<SHARES-COMMON-PRIOR> 1,600,181
<ACCUMULATED-NII-CURRENT> 19,112
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (20,684)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 40,901
<NET-ASSETS> 251,756,715
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 14,658,481
<OTHER-INCOME> 0
<EXPENSES-NET> 1,389,655
<NET-INVESTMENT-INCOME> 13,268,826
<REALIZED-GAINS-CURRENT> (2,536)
<APPREC-INCREASE-CURRENT> 62,387
<NET-CHANGE-FROM-OPS> 13,328,677
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 12,743,282
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 4,115,282
<NUMBER-OF-SHARES-REDEEMED> 4,129,942
<SHARES-REINVESTED> 84,589
<NET-CHANGE-IN-ASSETS> 10,386,302
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (18,160)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,143,154
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,394,367
<AVERAGE-NET-ASSETS> 253,471,522
<PER-SHARE-NAV-BEGIN> 150.84
<PER-SHARE-NII> 8.10
<PER-SHARE-GAIN-APPREC> 0.03
<PER-SHARE-DIVIDEND> (8.23)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 150.74
<EXPENSE-RATIO> 0.55
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 061
<NAME> Small CAP Value Equity Fund, Class A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 570,088,080
<INVESTMENTS-AT-VALUE> 689,246,997
<RECEIVABLES> 3,294,356
<ASSETS-OTHER> 669
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 692,542,022
<PAYABLE-FOR-SECURITIES> 747,964
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 8,474,273
<TOTAL-LIABILITIES> 9,222,237
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 564,160,868
<SHARES-COMMON-STOCK> 12,364
<SHARES-COMMON-PRIOR> 11,677
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 119,158,917
<NET-ASSETS> 173,948
<DIVIDEND-INCOME> 2,069
<INTEREST-INCOME> 670
<OTHER-INCOME> 0
<EXPENSES-NET> 2,382
<NET-INVESTMENT-INCOME> 357
<REALIZED-GAINS-CURRENT> 10,604
<APPREC-INCREASE-CURRENT> (29,485)
<NET-CHANGE-FROM-OPS> (18,524)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 1,413
<DISTRIBUTIONS-OF-GAINS> 17,099
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 11,008
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 1,356
<NET-CHANGE-IN-ASSETS> (18,523)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 2,217,759
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3,775,176
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 4,418,376
<AVERAGE-NET-ASSETS> 183,180
<PER-SHARE-NAV-BEGIN> 17.48
<PER-SHARE-NII> 0.03
<PER-SHARE-GAIN-APPREC> (1.78)
<PER-SHARE-DIVIDEND> (0.12)
<PER-SHARE-DISTRIBUTIONS> (1.54)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 14.07
<EXPENSE-RATIO> 1.30
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 062
<NAME> Small CAP Value Equity Fund, Class Y
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 570,088,080
<INVESTMENTS-AT-VALUE> 689,246,997
<RECEIVABLES> 3,294,356
<ASSETS-OTHER> 669
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 692,542,022
<PAYABLE-FOR-SECURITIES> 747,964
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 8,474,273
<TOTAL-LIABILITIES> 9,222,237
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 564,160,868
<SHARES-COMMON-STOCK> 40,399
<SHARES-COMMON-PRIOR> 23,731
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 119,158,917
<NET-ASSETS> 568,113
<DIVIDEND-INCOME> 4,574
<INTEREST-INCOME> 1,482
<OTHER-INCOME> 0
<EXPENSES-NET> 3,395
<NET-INVESTMENT-INCOME> 2,661
<REALIZED-GAINS-CURRENT> 21,871
<APPREC-INCREASE-CURRENT> (48,717)
<NET-CHANGE-FROM-OPS> (24,185)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 7,850
<DISTRIBUTIONS-OF-GAINS> 54,356
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 35,834
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 4,565
<NET-CHANGE-IN-ASSETS> 174,227
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 2,217,759
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3,775,176
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 4,418,376
<AVERAGE-NET-ASSETS> 398,417
<PER-SHARE-NAV-BEGIN> 17.51
<PER-SHARE-NII> 0.11
<PER-SHARE-GAIN-APPREC> (1.81)
<PER-SHARE-DIVIDEND> (0.21)
<PER-SHARE-DISTRIBUTIONS> (1.54)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 14.06
<EXPENSE-RATIO> 0.85
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 063
<NAME> Small CAP Value Equity Fund, Class S
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 570,088,080
<INVESTMENTS-AT-VALUE> 689,246,997
<RECEIVABLES> 3,294,356
<ASSETS-OTHER> 669
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 692,542,022
<PAYABLE-FOR-SECURITIES> 747,964
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 8,474,273
<TOTAL-LIABILITIES> 9,222,237
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 564,160,868
<SHARES-COMMON-STOCK> 48,544,773
<SHARES-COMMON-PRIOR> 41,565,529
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 119,158,917
<NET-ASSETS> 682,577,724
<DIVIDEND-INCOME> 7,784,318
<INTEREST-INCOME> 2,522,354
<OTHER-INCOME> 0
<EXPENSES-NET> 4,412,599
<NET-INVESTMENT-INCOME> 5,894,073
<REALIZED-GAINS-CURRENT> 38,383,903
<APPREC-INCREASE-CURRENT> (108,576,617)
<NET-CHANGE-FROM-OPS> (64,298,641)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 5,891,102
<DISTRIBUTIONS-OF-GAINS> 39,773,593
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 17,908,247
<NUMBER-OF-SHARES-REDEEMED> 14,284,755
<SHARES-REINVESTED> 3,355,752
<NET-CHANGE-IN-ASSETS> (7,800,576)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 2,217,759
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3,775,176
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 4,418,376
<AVERAGE-NET-ASSETS> 685,813,997
<PER-SHARE-NAV-BEGIN> 16.61
<PER-SHARE-NII> 0.13
<PER-SHARE-GAIN-APPREC> (1.67)
<PER-SHARE-DIVIDEND> (0.13)
<PER-SHARE-DISTRIBUTIONS> (0.88)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 14.06
<EXPENSE-RATIO> 0.64
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 041
<NAME> Balanced Fund, Class A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 618,057,462
<INVESTMENTS-AT-VALUE> 782,158,484
<RECEIVABLES> 7,979,713
<ASSETS-OTHER> 86,171
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 790,224,368
<PAYABLE-FOR-SECURITIES> 2,342,330
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 14,890,419
<TOTAL-LIABILITIES> 17,232,749
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 600,473,146
<SHARES-COMMON-STOCK> 12,465
<SHARES-COMMON-PRIOR> 11,560
<ACCUMULATED-NII-CURRENT> 32,992
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 8,384,459
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 164,101,022
<NET-ASSETS> 177,010
<DIVIDEND-INCOME> 1,910
<INTEREST-INCOME> 4,651
<OTHER-INCOME> 0
<EXPENSES-NET> 1,989
<NET-INVESTMENT-INCOME> 4,572
<REALIZED-GAINS-CURRENT> 9,267
<APPREC-INCREASE-CURRENT> 6,197
<NET-CHANGE-FROM-OPS> 20,036
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 6,590
<DISTRIBUTIONS-OF-GAINS> 11,583
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 11,185
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 1,280
<NET-CHANGE-IN-ASSETS> 20,035
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 6,196,048
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3,182,481
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 3,844,543
<AVERAGE-NET-ASSETS> 165,619
<PER-SHARE-NAV-BEGIN> 14.03
<PER-SHARE-NII> 0.41
<PER-SHARE-GAIN-APPREC> 1.36
<PER-SHARE-DIVIDEND> (0.58)
<PER-SHARE-DISTRIBUTIONS> (1.02)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 14.20
<EXPENSE-RATIO> 1.20
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 042
<NAME> Balanced Fund, Class Y
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 618,057,462
<INVESTMENTS-AT-VALUE> 782,158,484
<RECEIVABLES> 7,979,713
<ASSETS-OTHER> 86,171
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 790,224,368
<PAYABLE-FOR-SECURITIES> 2,342,330
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 14,890,419
<TOTAL-LIABILITIES> 17,232,749
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 600,473,146
<SHARES-COMMON-STOCK> 74,030
<SHARES-COMMON-PRIOR> 23,555
<ACCUMULATED-NII-CURRENT> 32,992
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 8,384,459
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 164,101,022
<NET-ASSETS> 1,051,256
<DIVIDEND-INCOME> 4,420
<INTEREST-INCOME> 10,764
<OTHER-INCOME> 0
<EXPENSES-NET> 2,903
<NET-INVESTMENT-INCOME> 12,281
<REALIZED-GAINS-CURRENT> 20,403
<APPREC-INCREASE-CURRENT> 20,520
<NET-CHANGE-FROM-OPS> 53,204
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 45,079
<DISTRIBUTIONS-OF-GAINS> 61,093
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 66,553
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 7,477
<NET-CHANGE-IN-ASSETS> 730,305
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 6,196,048
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3,182,481
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 3,844,543
<AVERAGE-NET-ASSETS> 383,143
<PER-SHARE-NAV-BEGIN> 14.06
<PER-SHARE-NII> 0.48
<PER-SHARE-GAIN-APPREC> 1.36
<PER-SHARE-DIVIDEND> (0.67)
<PER-SHARE-DISTRIBUTIONS> (1.03)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 14.20
<EXPENSE-RATIO> 0.76
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 043
<NAME> Balanced Fund, Class S
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 618,057,462
<INVESTMENTS-AT-VALUE> 782,158,484
<RECEIVABLES> 7,979,713
<ASSETS-OTHER> 86,171
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 790,224,368
<PAYABLE-FOR-SECURITIES> 2,342,330
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 14,890,419
<TOTAL-LIABILITIES> 17,232,749
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 600,473,146
<SHARES-COMMON-STOCK> 54,365,582
<SHARES-COMMON-PRIOR> 48,223,502
<ACCUMULATED-NII-CURRENT> 32,992
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 8,384,459
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 164,101,022
<NET-ASSETS> 771,763,353
<DIVIDEND-INCOME> 8,153,126
<INTEREST-INCOME> 19,853,622
<OTHER-INCOME> 0
<EXPENSES-NET> 3,839,651
<NET-INVESTMENT-INCOME> 24,167,097
<REALIZED-GAINS-CURRENT> 38,965,468
<APPREC-INCREASE-CURRENT> 24,912,768
<NET-CHANGE-FROM-OPS> 88,045,333
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 24,100,466
<DISTRIBUTIONS-OF-GAINS> 36,732,877
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 20,316,077
<NUMBER-OF-SHARES-REDEEMED> 18,473,081
<SHARES-REINVESTED> 4,299,084
<NET-CHANGE-IN-ASSETS> 116,628,148
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 6,196,048
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3,182,481
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 3,844,543
<AVERAGE-NET-ASSETS> 706,669,312
<PER-SHARE-NAV-BEGIN> 13.59
<PER-SHARE-NII> 0.49
<PER-SHARE-GAIN-APPREC> 1.33
<PER-SHARE-DIVIDEND> (0.48)
<PER-SHARE-DISTRIBUTIONS> (0.73)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 14.20
<EXPENSE-RATIO> 0.54
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 071
<NAME> International Equity Fund, Class A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 628,857,306
<INVESTMENTS-AT-VALUE> 641,732,931
<RECEIVABLES> 2,296,752
<ASSETS-OTHER> 290,435
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 644,320,118
<PAYABLE-FOR-SECURITIES> 168,505
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,016,263
<TOTAL-LIABILITIES> 3,184,768
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 623,001,417
<SHARES-COMMON-STOCK> 11,834
<SHARES-COMMON-PRIOR> 10,526
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 5,183,290
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 12,950,643
<NET-ASSETS> 134,583
<DIVIDEND-INCOME> 2,229
<INTEREST-INCOME> 252
<OTHER-INCOME> 0
<EXPENSES-NET> 2,343
<NET-INVESTMENT-INCOME> 138
<REALIZED-GAINS-CURRENT> 14,870
<APPREC-INCREASE-CURRENT> (9,367)
<NET-CHANGE-FROM-OPS> 5,641
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 1,652
<DISTRIBUTIONS-OF-GAINS> 15,476
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 10,066
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 1,768
<NET-CHANGE-IN-ASSETS> 5,641
<ACCUMULATED-NII-PRIOR> 293,037
<ACCUMULATED-GAINS-PRIOR> 16,328,165
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5,327,317
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 6,600,635
<AVERAGE-NET-ASSETS> 137,855
<PER-SHARE-NAV-BEGIN> 12.81
<PER-SHARE-NII> 0.01
<PER-SHARE-GAIN-APPREC> 0.53
<PER-SHARE-DIVIDEND> (0.12)
<PER-SHARE-DISTRIBUTIONS> (1.86)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 11.37
<EXPENSE-RATIO> 1.69
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 072
<NAME> International Equity Fund, Class Y
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 628,857,306
<INVESTMENTS-AT-VALUE> 641,732,931
<RECEIVABLES> 2,296,752
<ASSETS-OTHER> 290,435
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 644,320,118
<PAYABLE-FOR-SECURITIES> 168,505
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,016,263
<TOTAL-LIABILITIES> 3,184,768
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 623,001,417
<SHARES-COMMON-STOCK> 44,247
<SHARES-COMMON-PRIOR> 21,315
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 5,183,290
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 12,950,643
<NET-ASSETS> 502,918
<DIVIDEND-INCOME> 4,664
<INTEREST-INCOME> 528
<OTHER-INCOME> 0
<EXPENSES-NET> 3,864
<NET-INVESTMENT-INCOME> 1,328
<REALIZED-GAINS-CURRENT> 31,098
<APPREC-INCREASE-CURRENT> (7,585)
<NET-CHANGE-FROM-OPS> 24,841
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 6,174
<DISTRIBUTIONS-OF-GAINS> 57,831
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 38,055
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 6,192
<NET-CHANGE-IN-ASSETS> 239,685
<ACCUMULATED-NII-PRIOR> 293,037
<ACCUMULATED-GAINS-PRIOR> 16,328,165
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5,327,317
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 6,600,635
<AVERAGE-NET-ASSETS> 311,058
<PER-SHARE-NAV-BEGIN> 12.83
<PER-SHARE-NII> 0.06
<PER-SHARE-GAIN-APPREC> 0.55
<PER-SHARE-DIVIDEND> (0.21)
<PER-SHARE-DISTRIBUTIONS> (1.86)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 11.37
<EXPENSE-RATIO> 1.23
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 073
<NAME> International Equity Fund, Class S
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 628,857,306
<INVESTMENTS-AT-VALUE> 641,732,931
<RECEIVABLES> 2,296,752
<ASSETS-OTHER> 290,435
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 644,320,118
<PAYABLE-FOR-SECURITIES> 168,505
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,016,263
<TOTAL-LIABILITIES> 3,184,768
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 623,001,417
<SHARES-COMMON-STOCK> 56,352,157
<SHARES-COMMON-PRIOR> 44,180,338
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 5,183,290
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 12,950,643
<NET-ASSETS> 640,497,849
<DIVIDEND-INCOME> 10,011,648
<INTEREST-INCOME> 1,134,018
<OTHER-INCOME> 0
<EXPENSES-NET> 6,594,428
<NET-INVESTMENT-INCOME> 4,551,238
<REALIZED-GAINS-CURRENT> 65,552,194
<APPREC-INCREASE-CURRENT> (47,961,347)
<NET-CHANGE-FROM-OPS> 22,142,085
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 7,863,557
<DISTRIBUTIONS-OF-GAINS> 73,650,942
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 24,866,276
<NUMBER-OF-SHARES-REDEEMED> 19,794,239
<SHARES-REINVESTED> 7,099,782
<NET-CHANGE-IN-ASSETS> 93,708,090
<ACCUMULATED-NII-PRIOR> 293,037
<ACCUMULATED-GAINS-PRIOR> 16,328,165
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5,327,317
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 6,600,635
<AVERAGE-NET-ASSETS> 626,214,173
<PER-SHARE-NAV-BEGIN> 12.38
<PER-SHARE-NII> 0.10
<PER-SHARE-GAIN-APPREC> 0.51
<PER-SHARE-DIVIDEND> (0.17)
<PER-SHARE-DISTRIBUTIONS> (1.45)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 11.37
<EXPENSE-RATIO> 1.04
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 021
<NAME> Short Term Bond Fund, Class A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 280,602,336
<INVESTMENTS-AT-VALUE> 283,447,096
<RECEIVABLES> 1,208,411
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 131,503
<TOTAL-ASSETS> 284,787,010
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 715,678
<TOTAL-LIABILITIES> 715,678
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 281,302,233
<SHARES-COMMON-STOCK> 12,541
<SHARES-COMMON-PRIOR> 11,916
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (75,661)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 2,844,760
<NET-ASSETS> 129,354
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 7,739
<OTHER-INCOME> 0
<EXPENSES-NET> 1,507
<NET-INVESTMENT-INCOME> 6,232
<REALIZED-GAINS-CURRENT> 6
<APPREC-INCREASE-CURRENT> 681
<NET-CHANGE-FROM-OPS> 6,919
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 6,032
<DISTRIBUTIONS-OF-GAINS> 137
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 11,943
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 598
<NET-CHANGE-IN-ASSETS> 6,918
<ACCUMULATED-NII-PRIOR> 61,151
<ACCUMULATED-GAINS-PRIOR> 321,873
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,163,327
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,418,380
<AVERAGE-NET-ASSETS> 125,989
<PER-SHARE-NAV-BEGIN> 10.25
<PER-SHARE-NII> 0.52
<PER-SHARE-GAIN-APPREC> 0.05
<PER-SHARE-DIVIDEND> (0.50)
<PER-SHARE-DISTRIBUTIONS> (0.01)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.31
<EXPENSE-RATIO> 1.20
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 022
<NAME> Short Term Bond Fund, Class Y
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 280,602,336
<INVESTMENTS-AT-VALUE> 283,447,096
<RECEIVABLES> 1,208,411
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 131,503
<TOTAL-ASSETS> 284,787,010
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 715,678
<TOTAL-LIABILITIES> 715,678
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 281,302,233
<SHARES-COMMON-STOCK> 26,073
<SHARES-COMMON-PRIOR> 24,328
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (75,661)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 2,844,760
<NET-ASSETS> 268,784
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 15,878
<OTHER-INCOME> 0
<EXPENSES-NET> 1,907
<NET-INVESTMENT-INCOME> 13,971
<REALIZED-GAINS-CURRENT> 12
<APPREC-INCREASE-CURRENT> 1,396
<NET-CHANGE-FROM-OPS> 15,379
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 13,681
<DISTRIBUTIONS-OF-GAINS> 279
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 24,718
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 1,355
<NET-CHANGE-IN-ASSETS> 18,380
<ACCUMULATED-NII-PRIOR> 61,151
<ACCUMULATED-GAINS-PRIOR> 321,873
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,163,327
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,418,380
<AVERAGE-NET-ASSETS> 258,500
<PER-SHARE-NAV-BEGIN> 10.24
<PER-SHARE-NII> 0.57
<PER-SHARE-GAIN-APPREC> 0.06
<PER-SHARE-DIVIDEND> (0.55)
<PER-SHARE-DISTRIBUTIONS> (0.01)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.31
<EXPENSE-RATIO> 0.74
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from The MassMutual Institutional Funds, Inc
form N-SAR for the year ended December 31, 1998
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 023
<NAME> Short Term Bond Fund, Class S
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-END> DEC-31-1998
<INVESTMENTS-AT-COST> 280,602,336
<INVESTMENTS-AT-VALUE> 283,447,096
<RECEIVABLES> 1,208,411
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 131,503
<TOTAL-ASSETS> 284,787,010
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 715,678
<TOTAL-LIABILITIES> 715,678
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 281,302,233
<SHARES-COMMON-STOCK> 27,529,935
<SHARES-COMMON-PRIOR> 19,577,260
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (75,661)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 2,844,760
<NET-ASSETS> 283,673,194
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 15,822,361
<OTHER-INCOME> 0
<EXPENSES-NET> 1,414,966
<NET-INVESTMENT-INCOME> 14,407,395
<REALIZED-GAINS-CURRENT> (104,712)
<APPREC-INCREASE-CURRENT> 1,549,344
<NET-CHANGE-FROM-OPS> 15,852,027
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 14,459,636
<DISTRIBUTIONS-OF-GAINS> 321,463
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 17,247,226
<NUMBER-OF-SHARES-REDEEMED> 10,729,747
<SHARES-REINVESTED> 1,435,196
<NET-CHANGE-IN-ASSETS> 83,404,747
<ACCUMULATED-NII-PRIOR> 61,151
<ACCUMULATED-GAINS-PRIOR> 321,873
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,163,327
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,418,380
<AVERAGE-NET-ASSETS> 258,132,584
<PER-SHARE-NAV-BEGIN> 10.23
<PER-SHARE-NII> 0.56
<PER-SHARE-GAIN-APPREC> 0.08
<PER-SHARE-DIVIDEND> (0.56)
<PER-SHARE-DISTRIBUTIONS> (0.01)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.30
<EXPENSE-RATIO> 0.55
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
EXHIBIT INDEX TO FORM N-SAR
OF MASSMUTUAL INSTITUTIONAL FUNDS
FOR THE PERIOD ENDED DECEMBER 31, 1998
Exhibit No. Description
77B Accountant's Report on Internal Control (to be filed by amendment)
77J Revaluation of assets or restatement of capital share account
77K Changes in Registrant's certifying accountant
77Q(f) Letters from independent accountants furnished pursuant to
sub-item 77K
For Period Ended 12/31/98
File No. 811-8274
77J Revaluation of assets or restatement of capital share account
On February 1, 1999 the Board of Trustees of Registrant approved a reverse stock
split for Class A and Class Y shares of each series of Registrant. The reverse
sock split was effective as of February 5, 1999. The reverse stock split for the
Class A and Class Y shares was effected in connection with the decision by
Registrant's investment adviser and administrator to adjust the net asset value
for each Class A and Class Y share of each series to the net asset value for the
Class S share of each applicable series. Each series' Class A and Class Y shares
were give a conversion factor based on the closing net asset value for that
series' Class S shares on February 4, 1999. The conversion factors are listed in
a footnote to the financial statements that are included in the Annual Report to
Shareholders for the year ended December 31, 1999 and is incorporated herein by
reference.
Each shareholder may determine the number of shares it owns as a result of the
reverse stock split by multiplying the number of shares owned immediately prior
to the reverse stock split by the respective conversion factor. The reverse
stock split has not resulted in a change to shareholder account balances.
The Financial Statements have been restated to reflect the reverse stock splits.
For Period Ended 12/31/98
File No. 811-8274
77K Changes in Registrant's certifying accountant
After consultation with the staff of the Securities and Exchange Commission
(SEC) as a result of concerns regarding its independence with respect to
Registrant, PricewaterhouseCoopers LLP ("PwC") resigned as auditors of
Registrant, effective February 23, 1999. PwC's report on the financial
statements for the fiscal years 1996 and 1997 did not contain an adverse opinion
or a disclaimer of opinion, and was not qualified or modified as to uncertainty,
audit scope or accounting principles.
Registrant's Audit Committee recommended engaging Deloitte & Touche LLP as the
principal accountant to audit the Registrant's financial statements for fiscal
year 1998. A majority of Registrant's Board of Trustees, including a majority of
the independent Trustees, has approved the appointment of Deloitte & Touche LLP
as Registrant's independent auditors for Registrant's fiscal 1998 audit by
written consent, subject to (1) Deloitte & Touche LLP's certification to the
Board of Trustees that it is independent, (2) ratification of such appointment
at an in-person meeting of Registrant's Board of Trustees on or about March 26,
1999 and (3) the right of Registrant, by a majority vote of the shareholders at
any meeting called for that purpose, to terminate any appointment without
penalty.
For fiscal years 1997 and 1998, and during the period prior to PwC's
resignation, Registrant and PwC have not had any disagreements on any matter of
accounting principles or practices, financial statement disclosures, or auditing
scope or procedure, that either (1) have not been resolved to PwC's satisfaction
and (2) or, if not resolved to PwC's satisfaction, would have caused it to make
a reference to the subject matter of the disagreement in connection with its
report. Registrant has authorized PwC to respond fully to the inquiries of
Deloitte & Touche LLP, the successor accountant, concerning the subject matter
of any such disagreements.
Registrant discloses that no "reportable events" as defined in Item 304(a)(v)
existed for fiscal years 1997 and 1998 and during the period prior to PwC's
resignation, specifically: o PwC did not advise Registrant that the internal
controls necessary for Registrant to develop financial
statements do not exist;
o PwC did not advise Registrant that it can no longer rely on management's
representations, or that it was unwilling to be associated with the
financial statements prepared by management;
o PwC did not advise Registrant of the need to expand significantly the scope of
its audit; o PwC did not advise Registrant that information had come to its
attention that would materially impact
the fairness or reliability of either (i) a previously issued audit report
of the underlying financial statements, or (ii) the financial statements
issued or to be issued covering fiscal year 1998.
Registrant has not consulted Deloitte & Touche LLP on any accounting matters
prior to its engagement.
Pursuant to the requirements of Item 304(a)(3), Registrant has provided a copy
of this Item 77K to PwC. PwC has furnished Registrant with a letter addressed to
the SEC stating that it agrees with the statements made by Registrant herein. A
copy of such letter from PwC is attached hereto as an exhibit.
Item 77Q1(f) Letter from independent accountants furnished pursuant to
sub-items 77K
[PRICEWATERHOUSECOOPERS LETTERHEAD]
March 15, 1999
Securities and Exchange Commission
Judiciary Plaza
450 Fifth Street, N.W.
Washington, D.C. 20549
RE: MASSMUTUAL INSTITUTIONAL FUNDS (1933 Act File No. 33-73824;
1940 Act File No. 811-8274)
Ladies and Gentlemen:
PricewaterhouseCoopers LLP ("PwC") hereby furnishes this letter to the
Securities and Exchange Commission ("SEC") pursuant to Regulation section
229.304(a)(3) of the Exchange Act with respect to MassMutual Institutional Funds
("Registrant"). PwC agrees with the statements made by Registrant in Item 77K to
Registrant's N-SAR for the semi-annual period ending December 31, 1998.
Respectfully submitted,
PricewaterhouseCoopers LLP
March 15, 1999
Securities and Exchange Commission
Judiciary Plaza
450 Fifth Street, N.W.
Washington, D.C. 20549
RE: MASSMUTUAL INSTITUTIONAL FUNDS (1933 Act File No. 33-73824;
1940 Act File No. 811-8274); CIK Number: 0000916053
Ladies and Gentlemen:
Transmitted herewith for filing by means of electronic submission on behalf of
MassMutual Institutional Funds (the "Trust") is the semi-annual Form N-SAR for
the period ended December 31, 1998, pursuant to Section 30(a) of the Investment
Company Act of 1940, as amended (the "1940 Act") and Rule 30a-1 thereunder.
The Trust was advised to file its N-SAR for the period ending December 31, 1998,
by Kenneth Domingues, Chief Accountant, Division of Investment Management of the
Securities and Exchange Commission ("the "Commission") in a telephone
conversation with the undersigned on March 10, 1999. The Trust's Board of
Trustees approved PricewaterhouseCoopers, LLP ("PwC") as independent public
accountant for the Trust for fiscal year 1998 on February 1, 1999. Because of
concerns about PwC's independence and after consultation with the Commission,
PwC resigned as the Trust's independent public accountant on February 23, 1999,
prior to the completion of the Trust's audit for fiscal year 1998. Therefore,
the financial information supplied in the Trust's Form N-SAR is not based on
audited financial statements and could change when the Trust's fiscal year 1998
independent audit is completed. Additionally, because of PwC's resignation,
Exhibit 77B, the accountant's report on internal control, will be filed at a
later date.
Please address any comments or questions to the undersigned at (413) 744-8442.
Thank you in advance for your attention to this matter.
Very truly yours,
Jaqueline M. Hummel
Counsel
