<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000356013
<NAME> MERRILL LYNCH RETIREMENT SERIES TRUST
<SERIES>
<NUMBER> 012
<NAME> MERRILL LYNCH RETIREMENT RESERVES MONEY FUND
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> OCT-31-2000
<PERIOD-START> NOV-01-1999
<PERIOD-END> APR-30-2000
<INVESTMENTS-AT-COST> 14932959234
<INVESTMENTS-AT-VALUE> 14924330364
<RECEIVABLES> 82160891
<ASSETS-OTHER> 578109
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 15007069364
<PAYABLE-FOR-SECURITIES> 115007922
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 189008258
<TOTAL-LIABILITIES> 304016180
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 14711682054
<SHARES-COMMON-STOCK> 1025581116
<SHARES-COMMON-PRIOR> 1365751573
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> (8628870)
<NET-ASSETS> 1025069623
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 458606972
<OTHER-INCOME> 0
<EXPENSES-NET> (38885496)
<NET-INVESTMENT-INCOME> 419721476
<REALIZED-GAINS-CURRENT> (500617)
<APPREC-INCREASE-CURRENT> 5634572
<NET-CHANGE-FROM-OPS> 424855431
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (34199914)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 2753801747
<NUMBER-OF-SHARES-REDEEMED> (3128172421)
<SHARES-REINVESTED> 34200217
<NET-CHANGE-IN-ASSETS> (526706494)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 26555959
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 38885496
<AVERAGE-NET-ASSETS> 1293664999
<PER-SHARE-NAV-BEGIN> 1.00
<PER-SHARE-NII> .03
<PER-SHARE-GAIN-APPREC> 0
<PER-SHARE-DIVIDEND> (.03)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 1.00
<EXPENSE-RATIO> .69
</TABLE>