<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000320282
<NAME> SMITH BARNEY MUNICIPAL MONEY MARKET FUND, INC. CLASS Y
       
<S>                             <C>
<PERIOD-TYPE>                   YEAR
<FISCAL-YEAR-END>                          MAR-31-1997
<PERIOD-END>                               MAR-31-1997
<INVESTMENTS-AT-COST>                    5,488,577,006
<INVESTMENTS-AT-VALUE>                   5,488,577,006
<RECEIVABLES>                               88,345,381
<ASSETS-OTHER>                                 161,111
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                           5,577,083,498
<PAYABLE-FOR-SECURITIES>                             0
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                   10,166,511
<TOTAL-LIABILITIES>                         10,166,511
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                             0
<SHARES-COMMON-STOCK>                        4,755,401
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                            0
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                              0
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                             0
<NET-ASSETS>                             5,566,916,987
<DIVIDEND-INCOME>                                    0
<INTEREST-INCOME>                          192,373,989
<OTHER-INCOME>                                       0
<EXPENSES-NET>                              36,099,734
<NET-INVESTMENT-INCOME>                    156,274,255
<REALIZED-GAINS-CURRENT>                             0
<APPREC-INCREASE-CURRENT>                            0
<NET-CHANGE-FROM-OPS>                      156,205,821
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                      659,522
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                     92,552,190
<NUMBER-OF-SHARES-REDEEMED>                106,276,754
<SHARES-REINVESTED>                            670,860
<NET-CHANGE-IN-ASSETS>                     153,563,358
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                       26,073,153
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                             36,099,734
<AVERAGE-NET-ASSETS>                        22,011,994
<PER-SHARE-NAV-BEGIN>                             1.00
<PER-SHARE-NII>                                   .030
<PER-SHARE-GAIN-APPREC>                              0
<PER-SHARE-DIVIDEND>                            (.030)
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                               1.00
<EXPENSE-RATIO>                                   0.57
<AVG-DEBT-OUTSTANDING>                               0
<AVG-DEBT-PER-SHARE>                                 0
        


</TABLE>