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070 I020400 N
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<PAGE> PAGE 21
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<PAGE> PAGE 22
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008 A000501 MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
008 B000501 A
008 C000501 801-8059
008 D010501 SPRINGFIELD
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008 D030501 01111
008 A000502 DAVID L. BABSON AND COMPANY INCORPORATED
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015 A000501 INVESTORS BANK & TRUST COMPANY
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<PAGE> PAGE 23
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<PAGE> PAGE 24
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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
070 L010500 Y
070 L020500 Y
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<PAGE> PAGE 25
070 Q010500 N
070 Q020500 N
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<PAGE> PAGE 26
074 G000500 0
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008 A000601 MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
008 B000601 A
008 C000601 801-8059
008 D010601 SPRINGFIELD
008 D020601 MA
008 D030601 01111
008 A000602 DAVID L. BABSON AND COMPANY INCORPORATED
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015 A000601 INVESTORS BANK & TRUST COMPANY
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<PAGE> PAGE 27
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<PAGE> PAGE 28
055 A000600 N
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<PAGE> PAGE 29
070 L020600 N
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<PAGE> PAGE 30
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008 A000701 MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
008 B000701 A
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008 D010701 SPRINGFIELD
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015 A000701 INVESTORS BANK & TRUST COMPANY
015 B000701 C
<PAGE> PAGE 31
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015 A000703 CHASE MANHATTAN BANK
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015 A000704 NATIONAL AUSTRALIAN BANK
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015 A000705 EUROCLEAR
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015 A000706 STANDARD CHARTERED BANK
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015 A000707 BANKBOSTON
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015 C030707 02110
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015 A000709 BANCOMER SA
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<PAGE> PAGE 32
015 A000710 BARCLAYS BANK
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015 D020710 EC3N 4HJ
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015 A000711 THE STANDARD BANK OF SOUTH AFRICA LTD
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015 D010711 SOUTH AFRICA
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015 A000712 ROYAL TRUST CORPORATION OF CANADA
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024 000700 Y
025 A000701 CREDIT SUISSE GROUP
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<PAGE> PAGE 33
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<PAGE> PAGE 34
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<PAGE> PAGE 35
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<PAGE> PAGE 36
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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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 31
<NAME> Core Bond Fund, Class 1
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<ACCUMULATED-NET-GAINS> (2,088,284)
<OVERDISTRIBUTION-GAINS> 0
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<NET-ASSETS> 123,665
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 4,275
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<EXPENSES-NET> 999
<NET-INVESTMENT-INCOME> 3,276
<REALIZED-GAINS-CURRENT> (65)
<APPREC-INCREASE-CURRENT> (384)
<NET-CHANGE-FROM-OPS> 2,827
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<DISTRIBUTIONS-OF-INCOME> 0
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<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,827
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<GROSS-ADVISORY-FEES> 848,056
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<PER-SHARE-NAV-BEGIN> 10.50
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</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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 32
<NAME> Core Bond Fund, Class 2
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 400,421,776
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<ACCUMULATED-NET-GAINS> (2,088,284)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 3,620,605
<NET-ASSETS> 125,495
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 4,333
<OTHER-INCOME> 0
<EXPENSES-NET> 677
<NET-INVESTMENT-INCOME> 3,656
<REALIZED-GAINS-CURRENT> (66)
<APPREC-INCREASE-CURRENT> (388)
<NET-CHANGE-FROM-OPS> 3,202
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 3,202
<ACCUMULATED-NII-PRIOR> 1,845,746
<ACCUMULATED-GAINS-PRIOR> (1,885,881)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 848,056
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,043,718
<AVERAGE-NET-ASSETS> 122,878
<PER-SHARE-NAV-BEGIN> 10.51
<PER-SHARE-NII> 0.31
<PER-SHARE-GAIN-APPREC> (0.03)
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.79
<EXPENSE-RATIO> 1.11
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 33
<NAME> Core Bond Fund, Class 3
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 400,421,776
<INVESTMENTS-AT-VALUE> 404,065,980
<RECEIVABLES> 13,448,117
<ASSETS-OTHER> 1,302
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 417,515,399
<PAYABLE-FOR-SECURITIES> 135,859
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 316,687
<TOTAL-LIABILITIES> 452,546
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 401,263,451
<SHARES-COMMON-STOCK> 11,699
<SHARES-COMMON-PRIOR> 11,699
<ACCUMULATED-NII-CURRENT> 14,267,081
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (2,088,284)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 3,620,605
<NET-ASSETS> 126,549
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 4,365
<OTHER-INCOME> 0
<EXPENSES-NET> 468
<NET-INVESTMENT-INCOME> 3,897
<REALIZED-GAINS-CURRENT> (67)
<APPREC-INCREASE-CURRENT> (388)
<NET-CHANGE-FROM-OPS> 3,442
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 3,442
<ACCUMULATED-NII-PRIOR> 1,845,746
<ACCUMULATED-GAINS-PRIOR> (1,885,881)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 848,056
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,043,718
<AVERAGE-NET-ASSETS> 123,801
<PER-SHARE-NAV-BEGIN> 10.52
<PER-SHARE-NII> 0.33
<PER-SHARE-GAIN-APPREC> (0.03)
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.82
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 34
<NAME> Core Bond Fund, Class 4
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 400,421,776
<INVESTMENTS-AT-VALUE> 404,065,980
<RECEIVABLES> 13,448,117
<ASSETS-OTHER> 1,302
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 417,515,399
<PAYABLE-FOR-SECURITIES> 135,859
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 316,687
<TOTAL-LIABILITIES> 452,546
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 401,263,451
<SHARES-COMMON-STOCK> 38,753,822
<SHARES-COMMON-PRIOR> 34,141,922
<ACCUMULATED-NII-CURRENT> 14,267,081
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (2,088,284)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 3,620,605
<NET-ASSETS> 416,687,144
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 13,402,719
<OTHER-INCOME> 0
<EXPENSES-NET> 992,213
<NET-INVESTMENT-INCOME> 12,410,506
<REALIZED-GAINS-CURRENT> (202,205)
<APPREC-INCREASE-CURRENT> (1,086,558)
<NET-CHANGE-FROM-OPS> 11,121,743
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 9,449,800
<NUMBER-OF-SHARES-REDEEMED> 4,837,900
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 59,988,205
<ACCUMULATED-NII-PRIOR> 1,845,746
<ACCUMULATED-GAINS-PRIOR> (1,885,881)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 848,056
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,043,718
<AVERAGE-NET-ASSETS> 379,669,294
<PER-SHARE-NAV-BEGIN> 10.45
<PER-SHARE-NII> 0.34
<PER-SHARE-GAIN-APPREC> (0.04)
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.75
<EXPENSE-RATIO> 0.53
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 51
<NAME> Value Equity Fund, Class 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 1,932,556,830
<INVESTMENTS-AT-VALUE> 2,945,167,605
<RECEIVABLES> 22,562,796
<ASSETS-OTHER> 925
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 2,967,731,326
<PAYABLE-FOR-SECURITIES> 25,412,280
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 2,714,944
<TOTAL-LIABILITIES> 28,127,224
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 1,797,583,622
<SHARES-COMMON-STOCK> 10,640
<SHARES-COMMON-PRIOR> 10,640
<ACCUMULATED-NII-CURRENT> 26,785,147
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 103,624,558
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,012,610,775
<NET-ASSETS> 178,268
<DIVIDEND-INCOME> 2,038
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 1,349
<NET-INVESTMENT-INCOME> 689
<REALIZED-GAINS-CURRENT> 5,471
<APPREC-INCREASE-CURRENT> 18,502
<NET-CHANGE-FROM-OPS> 24,661
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 24,661
<ACCUMULATED-NII-PRIOR> 410,862
<ACCUMULATED-GAINS-PRIOR> 14,178,355
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5,958,697
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 7,312,891
<AVERAGE-NET-ASSETS> 163,489
<PER-SHARE-NAV-BEGIN> 14.44
<PER-SHARE-NII> 0.06
<PER-SHARE-GAIN-APPREC> 2.25
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 16.75
<EXPENSE-RATIO> 1.66
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 52
<NAME> Value Equity Fund, Class 2
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 1,932,556,830
<INVESTMENTS-AT-VALUE> 2,945,167,605
<RECEIVABLES> 22,562,796
<ASSETS-OTHER> 925
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 2,967,731,326
<PAYABLE-FOR-SECURITIES> 25,412,280
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 2,714,944
<TOTAL-LIABILITIES> 28,127,224
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 1,797,583,622
<SHARES-COMMON-STOCK> 10,740
<SHARES-COMMON-PRIOR> 10,740
<ACCUMULATED-NII-CURRENT> 26,785,147
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 103,624,558
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,012,610,775
<NET-ASSETS> 180,894
<DIVIDEND-INCOME> 2,066
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 914
<NET-INVESTMENT-INCOME> 1,152
<REALIZED-GAINS-CURRENT> 5,543
<APPREC-INCREASE-CURRENT> 18,752
<NET-CHANGE-FROM-OPS> 25,448
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 25,448
<ACCUMULATED-NII-PRIOR> 410,862
<ACCUMULATED-GAINS-PRIOR> 14,178,355
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5,958,697
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 7,312,891
<AVERAGE-NET-ASSETS> 165,673
<PER-SHARE-NAV-BEGIN> 14.47
<PER-SHARE-NII> 0.11
<PER-SHARE-GAIN-APPREC> 2.26
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 16.84
<EXPENSE-RATIO> 1.11
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 53
<NAME> Value Equity Fund, Class 3
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 1,932,556,830
<INVESTMENTS-AT-VALUE> 2,945,167,605
<RECEIVABLES> 22,562,796
<ASSETS-OTHER> 925
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 2,967,731,326
<PAYABLE-FOR-SECURITIES> 25,412,280
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 2,714,944
<TOTAL-LIABILITIES> 28,127,224
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 1,797,583,622
<SHARES-COMMON-STOCK> 10,793
<SHARES-COMMON-PRIOR> 10,793
<ACCUMULATED-NII-CURRENT> 26,785,147
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 103,624,558
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,012,610,775
<NET-ASSETS> 182,261
<DIVIDEND-INCOME> 2,079
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 633
<NET-INVESTMENT-INCOME> 1,446
<REALIZED-GAINS-CURRENT> 5,582
<APPREC-INCREASE-CURRENT> 18,882
<NET-CHANGE-FROM-OPS> 25,910
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 25,910
<ACCUMULATED-NII-PRIOR> 410,862
<ACCUMULATED-GAINS-PRIOR> 14,178,355
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5,958,697
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 7,312,891
<AVERAGE-NET-ASSETS> 166,782
<PER-SHARE-NAV-BEGIN> 14.49
<PER-SHARE-NII> 0.13
<PER-SHARE-GAIN-APPREC> 2.27
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 16.89
<EXPENSE-RATIO> 0.77
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 54
<NAME> Value Equity Fund, Class 4
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 1,932,556,830
<INVESTMENTS-AT-VALUE> 2,945,167,605
<RECEIVABLES> 22,562,796
<ASSETS-OTHER> 925
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 2,967,731,326
<PAYABLE-FOR-SECURITIES> 25,412,280
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 2,714,944
<TOTAL-LIABILITIES> 28,127,224
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 1,797,583,622
<SHARES-COMMON-STOCK> 174,174,339
<SHARES-COMMON-PRIOR> 171,928,663
<ACCUMULATED-NII-CURRENT> 26,785,147
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 103,624,558
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,012,610,775
<NET-ASSETS> 2,939,062,679
<DIVIDEND-INCOME> 33,289,978
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 6,918,980
<NET-INVESTMENT-INCOME> 26,370,998
<REALIZED-GAINS-CURRENT> 89,429,607
<APPREC-INCREASE-CURRENT> 300,696,713
<NET-CHANGE-FROM-OPS> 416,497,318
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 22,591,959
<NUMBER-OF-SHARES-REDEEMED> 20,346,283
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 453,319,848
<ACCUMULATED-NII-PRIOR> 410,862
<ACCUMULATED-GAINS-PRIOR> 14,178,355
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5,958,697
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 7,312,891
<AVERAGE-NET-ASSETS> 2,669,761,273
<PER-SHARE-NAV-BEGIN> 14.46
<PER-SHARE-NII> 0.15
<PER-SHARE-GAIN-APPREC> 2.26
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 16.87
<EXPENSE-RATIO> 0.52
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 11
<NAME> Prime Fund, Class 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 244,588,726
<INVESTMENTS-AT-VALUE> 244,596,563
<RECEIVABLES> 1,938,518
<ASSETS-OTHER> 2,640
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 246,537,721
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 1,583,158
<TOTAL-LIABILITIES> 1,583,158
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 238,247,351
<SHARES-COMMON-STOCK> 727
<SHARES-COMMON-PRIOR> 727
<ACCUMULATED-NII-CURRENT> 6,710,299
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (10,924)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 7,837
<NET-ASSETS> 111,959
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 3,139
<OTHER-INCOME> 0
<EXPENSES-NET> 912
<NET-INVESTMENT-INCOME> 2,227
<REALIZED-GAINS-CURRENT> (2)
<APPREC-INCREASE-CURRENT> 10
<NET-CHANGE-FROM-OPS> 2,235
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,235
<ACCUMULATED-NII-PRIOR> 80,676
<ACCUMULATED-GAINS-PRIOR> (7,151)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 576,162
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 706,077
<AVERAGE-NET-ASSETS> 110,811
<PER-SHARE-NAV-BEGIN> 151.03
<PER-SHARE-NII> 3.06
<PER-SHARE-GAIN-APPREC> 0.02
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 154.11
<EXPENSE-RATIO> 1.66
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 12
<NAME> Prime Fund, Class 2
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 244,588,726
<INVESTMENTS-AT-VALUE> 244,596,563
<RECEIVABLES> 1,938,518
<ASSETS-OTHER> 2,640
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 246,537,721
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 1,583,158
<TOTAL-LIABILITIES> 1,583,158
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 238,247,351
<SHARES-COMMON-STOCK> 734
<SHARES-COMMON-PRIOR> 734
<ACCUMULATED-NII-CURRENT> 6,710,299
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (10,924)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 7,837
<NET-ASSETS> 113,610
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 3,181
<OTHER-INCOME> 0
<EXPENSES-NET> 618
<NET-INVESTMENT-INCOME> 2,563
<REALIZED-GAINS-CURRENT> (2)
<APPREC-INCREASE-CURRENT> 9
<NET-CHANGE-FROM-OPS> 2,571
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,571
<ACCUMULATED-NII-PRIOR> 80,676
<ACCUMULATED-GAINS-PRIOR> (7,151)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 576,162
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 706,077
<AVERAGE-NET-ASSETS> 112,291
<PER-SHARE-NAV-BEGIN> 151.23
<PER-SHARE-NII> 3.49
<PER-SHARE-GAIN-APPREC> 0.01
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 154.73
<EXPENSE-RATIO> 1.11
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 13
<NAME> Prime Fund, Class 3
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 244,588,726
<INVESTMENTS-AT-VALUE> 244,596,563
<RECEIVABLES> 1,938,518
<ASSETS-OTHER> 2,640
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 246,537,721
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 1,583,158
<TOTAL-LIABILITIES> 1,583,158
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 238,247,351
<SHARES-COMMON-STOCK> 738
<SHARES-COMMON-PRIOR> 738
<ACCUMULATED-NII-CURRENT> 6,710,299
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (10,924)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 7,837
<NET-ASSETS> 114,477
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 3,203
<OTHER-INCOME> 0
<EXPENSES-NET> 427
<NET-INVESTMENT-INCOME> 2,776
<REALIZED-GAINS-CURRENT> (2)
<APPREC-INCREASE-CURRENT> 9
<NET-CHANGE-FROM-OPS> 2,783
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,783
<ACCUMULATED-NII-PRIOR> 80,676
<ACCUMULATED-GAINS-PRIOR> (7,151)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 576,162
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 706,077
<AVERAGE-NET-ASSETS> 113,050
<PER-SHARE-NAV-BEGIN> 151.29
<PER-SHARE-NII> 3.76
<PER-SHARE-GAIN-APPREC> 0.01
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 155.06
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 14
<NAME> Prime Fund, Class 4
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 244,588,726
<INVESTMENTS-AT-VALUE> 244,596,563
<RECEIVABLES> 1,938,518
<ASSETS-OTHER> 2,640
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 246,537,721
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 1,583,158
<TOTAL-LIABILITIES> 1,583,158
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 238,247,351
<SHARES-COMMON-STOCK> 1,578,771
<SHARES-COMMON-PRIOR> 1,713,474
<ACCUMULATED-NII-CURRENT> 6,710,299
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (10,924)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 7,837
<NET-ASSETS> 244,614,517
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 7,296,419
<OTHER-INCOME> 0
<EXPENSES-NET> 674,361
<NET-INVESTMENT-INCOME> 6,622,057
<REALIZED-GAINS-CURRENT> (3,768)
<APPREC-INCREASE-CURRENT> 15,897
<NET-CHANGE-FROM-OPS> 6,634,186
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 1,255,263
<NUMBER-OF-SHARES-REDEEMED> 1,389,966
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> (14,114,507)
<ACCUMULATED-NII-PRIOR> 80,676
<ACCUMULATED-GAINS-PRIOR> (7,151)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 576,162
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 706,077
<AVERAGE-NET-ASSETS> 257,857,991
<PER-SHARE-NAV-BEGIN> 151.00
<PER-SHARE-NII> 3.93
<PER-SHARE-GAIN-APPREC> 0.01
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 154.94
<EXPENSE-RATIO> 0.53
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 61
<NAME> Small CAP Value Equity Fund, Class 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 404,086,580
<INVESTMENTS-AT-VALUE> 568,708,309
<RECEIVABLES> 2,953,191
<ASSETS-OTHER> 839
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 571,662,339
<PAYABLE-FOR-SECURITIES> 4,764,297
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 734,984
<TOTAL-LIABILITIES> 5,499,281
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 372,384,505
<SHARES-COMMON-STOCK> 10,666
<SHARES-COMMON-PRIOR> 10,666
<ACCUMULATED-NII-CURRENT> 2,631,716
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 26,525,108
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 164,621,729
<NET-ASSETS> 164,885
<DIVIDEND-INCOME> 1,190
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 1,282
<NET-INVESTMENT-INCOME> (93)
<REALIZED-GAINS-CURRENT> 6,512
<APPREC-INCREASE-CURRENT> 15,653
<NET-CHANGE-FROM-OPS> 22,072
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 22,072
<ACCUMULATED-NII-PRIOR> 192,363
<ACCUMULATED-GAINS-PRIOR> 4,972,374
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,324,751
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,574,303
<AVERAGE-NET-ASSETS> 146,776
<PER-SHARE-NAV-BEGIN> 13.39
<PER-SHARE-NII> (0.01)
<PER-SHARE-GAIN-APPREC> 2.08
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 15.46
<EXPENSE-RATIO> 1.76
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 62
<NAME> Small CAP Value Equity Fund, Class 2
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 404,086,580
<INVESTMENTS-AT-VALUE> 568,708,309
<RECEIVABLES> 2,953,191
<ASSETS-OTHER> 839
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 571,662,339
<PAYABLE-FOR-SECURITIES> 4,764,297
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 734,984
<TOTAL-LIABILITIES> 5,499,281
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 372,384,505
<SHARES-COMMON-STOCK> 10,767
<SHARES-COMMON-PRIOR> 10,767
<ACCUMULATED-NII-CURRENT> 2,631,716
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 26,525,108
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 164,621,729
<NET-ASSETS> 167,340
<DIVIDEND-INCOME> 1,206
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 894
<NET-INVESTMENT-INCOME> 312
<REALIZED-GAINS-CURRENT> 6,600
<APPREC-INCREASE-CURRENT> 15,883
<NET-CHANGE-FROM-OPS> 22,795
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 22,795
<ACCUMULATED-NII-PRIOR> 192,363
<ACCUMULATED-GAINS-PRIOR> 4,972,374
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,324,751
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,574,303
<AVERAGE-NET-ASSETS> 148,761
<PER-SHARE-NAV-BEGIN> 13.42
<PER-SHARE-NII> 0.03
<PER-SHARE-GAIN-APPREC> 2.09
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 15.54
<EXPENSE-RATIO> 1.21
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 63
<NAME> Small CAP Value Equity Fund, Class 3
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 404,086,580
<INVESTMENTS-AT-VALUE> 568,708,309
<RECEIVABLES> 2,953,191
<ASSETS-OTHER> 839
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 571,662,339
<PAYABLE-FOR-SECURITIES> 4,764,297
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 734,984
<TOTAL-LIABILITIES> 5,499,281
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 372,384,505
<SHARES-COMMON-STOCK> 10,837
<SHARES-COMMON-PRIOR> 10,837
<ACCUMULATED-NII-CURRENT> 2,631,716
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 26,525,108
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 164,621,729
<NET-ASSETS> 168,863
<DIVIDEND-INCOME> 1,216
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 643
<NET-INVESTMENT-INCOME> 573
<REALIZED-GAINS-CURRENT> 6,654
<APPREC-INCREASE-CURRENT> 16,027
<NET-CHANGE-FROM-OPS> 23,254
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 23,254
<ACCUMULATED-NII-PRIOR> 192,363
<ACCUMULATED-GAINS-PRIOR> 4,972,374
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,324,751
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,574,303
<AVERAGE-NET-ASSETS> 149,987
<PER-SHARE-NAV-BEGIN> 13.44
<PER-SHARE-NII> 0.05
<PER-SHARE-GAIN-APPREC> 2.09
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 15.58
<EXPENSE-RATIO> 0.86
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 64
<NAME> Small CAP Value Equity Fund, Class 4
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 404,086,580
<INVESTMENTS-AT-VALUE> 568,708,309
<RECEIVABLES> 2,953,191
<ASSETS-OTHER> 839
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 571,662,339
<PAYABLE-FOR-SECURITIES> 4,764,297
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 734,984
<TOTAL-LIABILITIES> 5,499,281
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 372,384,505
<SHARES-COMMON-STOCK> 36,265,588
<SHARES-COMMON-PRIOR> 34,013,589
<ACCUMULATED-NII-CURRENT> 2,631,716
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 26,525,108
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 164,621,729
<NET-ASSETS> 565,661,970
<DIVIDEND-INCOME> 3,944,374
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 1,505,813
<NET-INVESTMENT-INCOME> 2,438,560
<REALIZED-GAINS-CURRENT> 21,532,969
<APPREC-INCREASE-CURRENT> 53,164,597
<NET-CHANGE-FROM-OPS> 77,136,127
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 6,601,406
<NUMBER-OF-SHARES-REDEEMED> 4,349,407
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 108,726,554
<ACCUMULATED-NII-PRIOR> 192,363
<ACCUMULATED-GAINS-PRIOR> 4,972,374
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,324,751
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,574,303
<AVERAGE-NET-ASSETS> 485,274,476
<PER-SHARE-NAV-BEGIN> 13.43
<PER-SHARE-NII> 0.07
<PER-SHARE-GAIN-APPREC> 2.10
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 15.60
<EXPENSE-RATIO> 0.63
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 41
<NAME> Balanced Fund, Class 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 505,416,393
<INVESTMENTS-AT-VALUE> 628,163,436
<RECEIVABLES> 4,204,369
<ASSETS-OTHER> 8,223
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 632,376,028
<PAYABLE-FOR-SECURITIES> 3,102,397
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 582,570
<TOTAL-LIABILITIES> 3,684,967
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 483,414,936
<SHARES-COMMON-STOCK> 10,838
<SHARES-COMMON-PRIOR> 10,838
<ACCUMULATED-NII-CURRENT> 10,713,433
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 11,820,496
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 122,742,196
<NET-ASSETS> 146,563
<DIVIDEND-INCOME> 2,890
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 1,144
<NET-INVESTMENT-INCOME> 1,746
<REALIZED-GAINS-CURRENT> 2,333
<APPREC-INCREASE-CURRENT> 8,663
<NET-CHANGE-FROM-OPS> 12,742
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 12,742
<ACCUMULATED-NII-PRIOR> 26,102
<ACCUMULATED-GAINS-PRIOR> 1,920,993
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,309,860
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,606,234
<AVERAGE-NET-ASSETS> 138,873
<PER-SHARE-NAV-BEGIN> 12.35
<PER-SHARE-NII> 0.16
<PER-SHARE-GAIN-APPREC> 1.01
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 13.52
<EXPENSE-RATIO> 1.66
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 42
<NAME> Balanced Fund, Class 2
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 505,416,393
<INVESTMENTS-AT-VALUE> 628,163,436
<RECEIVABLES> 4,204,369
<ASSETS-OTHER> 8,223
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 632,376,028
<PAYABLE-FOR-SECURITIES> 3,102,397
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 582,570
<TOTAL-LIABILITIES> 3,684,967
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 483,414,936
<SHARES-COMMON-STOCK> 10,948
<SHARES-COMMON-PRIOR> 10,948
<ACCUMULATED-NII-CURRENT> 10,713,433
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 11,820,496
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 122,742,196
<NET-ASSETS> 148,717
<DIVIDEND-INCOME> 2,928
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 775
<NET-INVESTMENT-INCOME> 2,153
<REALIZED-GAINS-CURRENT> 2,364
<APPREC-INCREASE-CURRENT> 8,782
<NET-CHANGE-FROM-OPS> 13,299
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 13,299
<ACCUMULATED-NII-PRIOR> 26,102
<ACCUMULATED-GAINS-PRIOR> 1,920,993
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,309,860
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,606,234
<AVERAGE-NET-ASSETS> 140,722
<PER-SHARE-NAV-BEGIN> 12.37
<PER-SHARE-NII> 0.20
<PER-SHARE-GAIN-APPREC> 1.01
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 13.58
<EXPENSE-RATIO> 1.11
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 43
<NAME> Balanced Fund, Class 3
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 505,416,393
<INVESTMENTS-AT-VALUE> 628,163,436
<RECEIVABLES> 4,204,369
<ASSETS-OTHER> 8,223
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 632,376,028
<PAYABLE-FOR-SECURITIES> 3,102,397
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 582,570
<TOTAL-LIABILITIES> 3,684,967
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 483,414,936
<SHARES-COMMON-STOCK> 10,994
<SHARES-COMMON-PRIOR> 10,994
<ACCUMULATED-NII-CURRENT> 10,713,433
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 11,820,496
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 122,742,196
<NET-ASSETS> 149,854
<DIVIDEND-INCOME> 2,948
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 536
<NET-INVESTMENT-INCOME> 2,412
<REALIZED-GAINS-CURRENT> 2,381
<APPREC-INCREASE-CURRENT> 8,844
<NET-CHANGE-FROM-OPS> 13,636
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 13,636
<ACCUMULATED-NII-PRIOR> 26,102
<ACCUMULATED-GAINS-PRIOR> 1,920,993
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,309,860
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,606,234
<AVERAGE-NET-ASSETS> 141,676
<PER-SHARE-NAV-BEGIN> 12.39
<PER-SHARE-NII> 0.22
<PER-SHARE-GAIN-APPREC> 1.02
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 13.63
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 44
<NAME> Balanced Fund, Class 4
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 505,416,393
<INVESTMENTS-AT-VALUE> 628,163,436
<RECEIVABLES> 4,204,369
<ASSETS-OTHER> 8,223
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 632,376,028
<PAYABLE-FOR-SECURITIES> 3,102,397
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 582,570
<TOTAL-LIABILITIES> 3,684,967
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 483,414,936
<SHARES-COMMON-STOCK> 46,209,722
<SHARES-COMMON-PRIOR> 45,632,444
<ACCUMULATED-NII-CURRENT> 10,713,433
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 11,820,496
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 122,742,196
<NET-ASSETS> 628,245,927
<DIVIDEND-INCOME> 12,209,805
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 1,528,784
<NET-INVESTMENT-INCOME> 10,681,021
<REALIZED-GAINS-CURRENT> 9,892,425
<APPREC-INCREASE-CURRENT> 36,622,959
<NET-CHANGE-FROM-OPS> 57,196,405
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 8,196,028
<NUMBER-OF-SHARES-REDEEMED> 7,618,750
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 64,965,536
<ACCUMULATED-NII-PRIOR> 26,102
<ACCUMULATED-GAINS-PRIOR> 1,920,993
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,309,860
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,606,234
<AVERAGE-NET-ASSETS> 586,563,229
<PER-SHARE-NAV-BEGIN> 12.34
<PER-SHARE-NII> 0.23
<PER-SHARE-GAIN-APPREC> 1.03
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 13.60
<EXPENSE-RATIO> 0.53
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 71
<NAME> International Equity Fund, Class 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 424,095,948
<INVESTMENTS-AT-VALUE> 523,233,075
<RECEIVABLES> 17,098,234
<ASSETS-OTHER> 3,821,648
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 544,152,957
<PAYABLE-FOR-SECURITIES> 24,152,987
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,826,107
<TOTAL-LIABILITIES> 27,979,094
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 413,449,144
<SHARES-COMMON-STOCK> 10,176
<SHARES-COMMON-PRIOR> 10,176
<ACCUMULATED-NII-CURRENT> 2,786,109
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 3,725,014
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 96,213,596
<NET-ASSETS> 130,571
<DIVIDEND-INCOME> 1,323
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 1,324
<NET-INVESTMENT-INCOME> (1)
<REALIZED-GAINS-CURRENT> 4,273
<APPREC-INCREASE-CURRENT> 13,602
<NET-CHANGE-FROM-OPS> 17,874
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 17,890
<ACCUMULATED-NII-PRIOR> 113,978
<ACCUMULATED-GAINS-PRIOR> (12,355,482)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,804,870
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 2,274,676
<AVERAGE-NET-ASSETS> 120,385
<PER-SHARE-NAV-BEGIN> 11.07
<PER-SHARE-NII> 0.00
<PER-SHARE-GAIN-APPREC> 1.76
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 12.83
<EXPENSE-RATIO> 2.17
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 72
<NAME> International Equity Fund, Class 2
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 424,095,948
<INVESTMENTS-AT-VALUE> 523,233,075
<RECEIVABLES> 17,098,234
<ASSETS-OTHER> 3,821,648
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 544,152,957
<PAYABLE-FOR-SECURITIES> 24,152,987
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,826,107
<TOTAL-LIABILITIES> 27,979,094
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 413,449,144
<SHARES-COMMON-STOCK> 10,281
<SHARES-COMMON-PRIOR> 10,281
<ACCUMULATED-NII-CURRENT> 2,786,109
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 3,725,014
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 96,213,596
<NET-ASSETS> 132,483
<DIVIDEND-INCOME> 1,341
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 1,001
<NET-INVESTMENT-INCOME> 340
<REALIZED-GAINS-CURRENT> 4,332
<APPREC-INCREASE-CURRENT> 13,782
<NET-CHANGE-FROM-OPS> 18,455
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 18,464
<ACCUMULATED-NII-PRIOR> 113,978
<ACCUMULATED-GAINS-PRIOR> (12,355,482)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,804,870
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 2,274,676
<AVERAGE-NET-ASSETS> 121,983
<PER-SHARE-NAV-BEGIN> 11.09
<PER-SHARE-NII> 0.03
<PER-SHARE-GAIN-APPREC> 1.77
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 12.89
<EXPENSE-RATIO> 1.62
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 73
<NAME> International Equity Fund, Class 3
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 424,095,948
<INVESTMENTS-AT-VALUE> 523,233,075
<RECEIVABLES> 17,098,234
<ASSETS-OTHER> 3,821,648
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 544,152,957
<PAYABLE-FOR-SECURITIES> 24,152,987
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,826,107
<TOTAL-LIABILITIES> 27,979,094
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 413,449,144
<SHARES-COMMON-STOCK> 10,315
<SHARES-COMMON-PRIOR> 10,315
<ACCUMULATED-NII-CURRENT> 2,786,109
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 3,725,014
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 96,213,596
<NET-ASSETS> 133,169
<DIVIDEND-INCOME> 1,348
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 850
<NET-INVESTMENT-INCOME> 497
<REALIZED-GAINS-CURRENT> 4,353
<APPREC-INCREASE-CURRENT> 13,845
<NET-CHANGE-FROM-OPS> 18,696
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 18,701
<ACCUMULATED-NII-PRIOR> 113,978
<ACCUMULATED-GAINS-PRIOR> (12,355,482)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,804,870
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 2,274,676
<AVERAGE-NET-ASSETS> 122,540
<PER-SHARE-NAV-BEGIN> 11.10
<PER-SHARE-NII> 0.05
<PER-SHARE-GAIN-APPREC> 1.76
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 12.91
<EXPENSE-RATIO> 1.37
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 74
<NAME> International Equity Fund, Class 4
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 424,095,948
<INVESTMENTS-AT-VALUE> 523,233,075
<RECEIVABLES> 17,098,234
<ASSETS-OTHER> 3,821,648
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 544,152,957
<PAYABLE-FOR-SECURITIES> 24,152,987
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,826,107
<TOTAL-LIABILITIES> 27,979,094
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 413,449,144
<SHARES-COMMON-STOCK> 39,835,590
<SHARES-COMMON-PRIOR> 32,070,618
<ACCUMULATED-NII-CURRENT> 2,786,109
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 3,725,014
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 96,213,596
<NET-ASSETS> 515,777,640
<DIVIDEND-INCOME> 4,892,042
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 2,220,747
<NET-INVESTMENT-INCOME> 2,671,295
<REALIZED-GAINS-CURRENT> 16,067,537
<APPREC-INCREASE-CURRENT> 48,269,631
<NET-CHANGE-FROM-OPS> 67,008,463
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 12,137,572
<NUMBER-OF-SHARES-REDEEMED> 4,372,600
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 159,466,996
<ACCUMULATED-NII-PRIOR> 113,978
<ACCUMULATED-GAINS-PRIOR> (12,355,482)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,804,870
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 2,274,676
<AVERAGE-NET-ASSETS> 427,829,745
<PER-SHARE-NAV-BEGIN> 11.11
<PER-SHARE-NII> 0.07
<PER-SHARE-GAIN-APPREC> 1.77
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 12.95
<EXPENSE-RATIO> 1.02
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 21
<NAME> Short Term Bond Fund, Class 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 164,941,091
<INVESTMENTS-AT-VALUE> 165,183,286
<RECEIVABLES> 7,481,776
<ASSETS-OTHER> 426
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 172,665,488
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 242,546
<TOTAL-LIABILITIES> 242,546
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 167,618,985
<SHARES-COMMON-STOCK> 11,415
<SHARES-COMMON-PRIOR> 11,415
<ACCUMULATED-NII-CURRENT> 4,939,839
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (378,077)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 242,195
<NET-ASSETS> 118,259
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 3,998
<OTHER-INCOME> 0
<EXPENSES-NET> 958
<NET-INVESTMENT-INCOME> 3,039
<REALIZED-GAINS-CURRENT> (62)
<APPREC-INCREASE-CURRENT> (582)
<NET-CHANGE-FROM-OPS> 2,396
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,396
<ACCUMULATED-NII-PRIOR> 18,783
<ACCUMULATED-GAINS-PRIOR> (295,200)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 346,373
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 428,049
<AVERAGE-NET-ASSETS> 116,502
<PER-SHARE-NAV-BEGIN> 10.15
<PER-SHARE-NII> 0.27
<PER-SHARE-GAIN-APPREC> (0.06)
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.36
<EXPENSE-RATIO> 1.66
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 22
<NAME> Short Term Bond Fund, Class 2
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 164,941,091
<INVESTMENTS-AT-VALUE> 165,183,286
<RECEIVABLES> 7,481,776
<ASSETS-OTHER> 426
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 172,665,488
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 242,546
<TOTAL-LIABILITIES> 242,546
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 167,618,985
<SHARES-COMMON-STOCK> 11,544
<SHARES-COMMON-PRIOR> 11,544
<ACCUMULATED-NII-CURRENT> 4,939,839
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (378,077)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 242,195
<NET-ASSETS> 120,003
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 4,051
<OTHER-INCOME> 0
<EXPENSES-NET> 649
<NET-INVESTMENT-INCOME> 3,402
<REALIZED-GAINS-CURRENT> (63)
<APPREC-INCREASE-CURRENT> (586)
<NET-CHANGE-FROM-OPS> 2,753
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,753
<ACCUMULATED-NII-PRIOR> 18,783
<ACCUMULATED-GAINS-PRIOR> (295,200)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 346,373
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 428,049
<AVERAGE-NET-ASSETS> 118,057
<PER-SHARE-NAV-BEGIN> 10.16
<PER-SHARE-NII> 0.29
<PER-SHARE-GAIN-APPREC> (0.05)
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.40
<EXPENSE-RATIO> 1.11
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 23
<NAME> Short Term Bond Fund, Class 3
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 164,941,091
<INVESTMENTS-AT-VALUE> 165,183,286
<RECEIVABLES> 7,481,776
<ASSETS-OTHER> 426
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 172,665,488
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 242,546
<TOTAL-LIABILITIES> 242,546
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 167,618,985
<SHARES-COMMON-STOCK> 11,599
<SHARES-COMMON-PRIOR> 11,599
<ACCUMULATED-NII-CURRENT> 4,939,839
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (378,077)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 242,195
<NET-ASSETS> 120,979
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 4,081
<OTHER-INCOME> 0
<EXPENSES-NET> 449
<NET-INVESTMENT-INCOME> 3,632
<REALIZED-GAINS-CURRENT> (63)
<APPREC-INCREASE-CURRENT> (590)
<NET-CHANGE-FROM-OPS> 2,978
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,978
<ACCUMULATED-NII-PRIOR> 18,783
<ACCUMULATED-GAINS-PRIOR> (295,200)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 346,373
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 428,049
<AVERAGE-NET-ASSETS> 118,914
<PER-SHARE-NAV-BEGIN> 10.17
<PER-SHARE-NII> 0.31
<PER-SHARE-GAIN-APPREC> (0.05)
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.43
<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 period ended June 30, 1997
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 24
<NAME> Short Term Bond Fund, Class 4
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-END> JUN-30-1997
<INVESTMENTS-AT-COST> 164,941,091
<INVESTMENTS-AT-VALUE> 165,183,286
<RECEIVABLES> 7,481,776
<ASSETS-OTHER> 426
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 172,665,488
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 242,546
<TOTAL-LIABILITIES> 242,546
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 167,618,985
<SHARES-COMMON-STOCK> 16,587,139
<SHARES-COMMON-PRIOR> 14,365,202
<ACCUMULATED-NII-CURRENT> 4,939,839
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (378,077)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 242,195
<NET-ASSETS> 172,063,701
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 5,318,729
<OTHER-INCOME> 0
<EXPENSES-NET> 407,746
<NET-INVESTMENT-INCOME> 4,910,983
<REALIZED-GAINS-CURRENT> (82,690)
<APPREC-INCREASE-CURRENT> (773,776)
<NET-CHANGE-FROM-OPS> 4,054,518
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 4,745,250
<NUMBER-OF-SHARES-REDEEMED> 2,523,313
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 26,881,406
<ACCUMULATED-NII-PRIOR> 18,783
<ACCUMULATED-GAINS-PRIOR> (295,200)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 346,373
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 428,049
<AVERAGE-NET-ASSETS> 154,865,935
<PER-SHARE-NAV-BEGIN> 10.11
<PER-SHARE-NII> 0.32
<PER-SHARE-GAIN-APPREC> (0.06)
<PER-SHARE-DIVIDEND> 0.00
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.37
<EXPENSE-RATIO> 0.53
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0.00
</TABLE>
