[ARTICLE] 6
[CIK] 0000320282
[NAME] SMITH BARNEY MUNICIPAL MONEY MARKET FUND, INC. CLASS Y
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   6-MOS
[FISCAL-YEAR-END]                          MAR-31-1996
[PERIOD-END]                               SEP-30-1996
[INVESTMENTS-AT-COST]                    5,267,471,554
[INVESTMENTS-AT-VALUE]                   5,267,471,554
[RECEIVABLES]                               29,348,209
[ASSETS-OTHER]                                 376,826
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                           5,297,196,589
[PAYABLE-FOR-SECURITIES]                   167,001,731
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                    9,113,551
[TOTAL-LIABILITIES]                        176,115,282
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                             0
[SHARES-COMMON-STOCK]                        5,148,363
[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]                             5,121,081,307
[DIVIDEND-INCOME]                                    0
[INTEREST-INCOME]                                    0
[OTHER-INCOME]                                       0
[EXPENSES-NET]                              17,861,200
[NET-INVESTMENT-INCOME]                     77,864,877
[REALIZED-GAINS-CURRENT]                             0
[APPREC-INCREASE-CURRENT]                            0
[NET-CHANGE-FROM-OPS]                       77,774,649
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                      463,232
[DISTRIBUTIONS-OF-GAINS]                             0
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                     58,042,301
[NUMBER-OF-SHARES-REDEEMED]                 71,185,188
[SHARES-REINVESTED]                            482,144
[NET-CHANGE-IN-ASSETS]                   (292,272,322)
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                            0
[OVERDISTRIB-NII-PRIOR]                              0
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                       12,898,294
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                             17,861,200
[AVERAGE-NET-ASSETS]                        30,890,595
[PER-SHARE-NAV-BEGIN]                             1.00
[PER-SHARE-NII]                                  0.015
[PER-SHARE-GAIN-APPREC]                              0
[PER-SHARE-DIVIDEND]                             0.015
[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>