<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
this schedule contains summary financial information extracted from mason street
funds, inc. aggressive growth stock fund, 03/31/00 financial statements class a.
</LEGEND>
<CIK> 0001023744
<NAME> MASON STREET FUNDS, INC.
<SERIES>
<NUMBER> 021
<NAME> AGGRESSIVE GROWTH STOCK FUND CLASS A
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> MAR-31-2000
<PERIOD-START> APR-01-1999
<PERIOD-END> MAR-31-2000
<INVESTMENTS-AT-COST> 56656510
<INVESTMENTS-AT-VALUE> 93172352
<RECEIVABLES> 4638424
<ASSETS-OTHER> 239244
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 98050020
<PAYABLE-FOR-SECURITIES> 1665004
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 135811
<TOTAL-LIABILITIES> 1800815
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 49644742
<SHARES-COMMON-STOCK> 3651913
<SHARES-COMMON-PRIOR> 3538371
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 10088621
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 36515842
<NET-ASSETS> 96249205
<DIVIDEND-INCOME> 47910
<INTEREST-INCOME> 275854
<OTHER-INCOME> 0
<EXPENSES-NET> 918698
<NET-INVESTMENT-INCOME> (594934)
<REALIZED-GAINS-CURRENT> 16585769
<APPREC-INCREASE-CURRENT> 27872951
<NET-CHANGE-FROM-OPS> 43863786
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 6860994
<DISTRIBUTIONS-OF-GAINS> 860509
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 258390
<NUMBER-OF-SHARES-REDEEMED> 149669
<SHARES-REINVESTED> 350616
<NET-CHANGE-IN-ASSETS> 47713520
<ACCUMULATED-NII-PRIOR> (372860)
<ACCUMULATED-GAINS-PRIOR> 2546341
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 504716
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1054486
<AVERAGE-NET-ASSETS> 0
<PER-SHARE-NAV-BEGIN> 13.73
<PER-SHARE-NII> (0.21)
<PER-SHARE-GAIN-APPREC> 11.82
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> 2.11
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 23.23
<EXPENSE-RATIO> 1.30
</TABLE>
