<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
this schedule contains summary financial information extracted from mason street
funds, inc. municipal bond fund, 03/31/00 financial statements class a.
</LEGEND>
<CIK> 0001023744
<NAME> MASON STREET FUNDS, INC.
<SERIES>
<NUMBER> 101
<NAME> MUNICIPAL BOND 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> 36342173
<INVESTMENTS-AT-VALUE> 36230540
<RECEIVABLES> 6187017
<ASSETS-OTHER> 13680
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 42431237
<PAYABLE-FOR-SECURITIES> 8040696
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 26151
<TOTAL-LIABILITIES> 8066847
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 34499082
<SHARES-COMMON-STOCK> 3325015
<SHARES-COMMON-PRIOR> 3074553
<ACCUMULATED-NII-CURRENT> 34006
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (57065)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> (111633)
<NET-ASSETS> 34364390
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 1821849
<OTHER-INCOME> 0
<EXPENSES-NET> 287317
<NET-INVESTMENT-INCOME> 1534532
<REALIZED-GAINS-CURRENT> 52610
<APPREC-INCREASE-CURRENT> (1628806)
<NET-CHANGE-FROM-OPS> (41664)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 1498709
<DISTRIBUTIONS-OF-GAINS> 242842
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 123222
<NUMBER-OF-SHARES-REDEEMED> 32459
<SHARES-REINVESTED> 159699
<NET-CHANGE-IN-ASSETS> 822834
<ACCUMULATED-NII-PRIOR> 29775
<ACCUMULATED-GAINS-PRIOR> 139615
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 101337
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 389702
<AVERAGE-NET-ASSETS> 0
<PER-SHARE-NAV-BEGIN> 10.63
<PER-SHARE-NII> 0.46
<PER-SHARE-GAIN-APPREC> (0.49)
<PER-SHARE-DIVIDEND> 0.46
<PER-SHARE-DISTRIBUTIONS> 0.07
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 10.07
<EXPENSE-RATIO> 0.85
</TABLE>
