<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000320282
<NAME> Smith Barney Municipal Money Market Fund, Inc.

<S>                             <C>
<PERIOD-TYPE>                  6-MOS
<FISCAL-YEAR-END>                               Mar-31-2001
<PERIOD-END>                                    Sep-30-2000
<INVESTMENTS-AT-COST>                         7,435,293,615
<INVESTMENTS-AT-VALUE>                        7,435,293,615
<RECEIVABLES>                                    49,176,022
<ASSETS-OTHER>                                      453,728
<OTHER-ITEMS-ASSETS>                                      0
<TOTAL-ASSETS>                                7,484,923,365
<PAYABLE-FOR-SECURITIES>                        319,032,050
<SENIOR-LONG-TERM-DEBT>                                   0
<OTHER-ITEMS-LIABILITIES>                        19,504,147
<TOTAL-LIABILITIES>                             338,536,197
<SENIOR-EQUITY>                                           0
<PAID-IN-CAPITAL-COMMON>                      7,146,558,611
<SHARES-COMMON-STOCK>                               210,626
<SHARES-COMMON-PRIOR>                               461,147
<ACCUMULATED-NII-CURRENT>                                 0
<OVERDISTRIBUTION-NII>                                    0
<ACCUMULATED-NET-GAINS>                                   0
<OVERDISTRIBUTION-GAINS>                                  0
<ACCUM-APPREC-OR-DEPREC>                           (171,443)
<NET-ASSETS>                                  7,146,387,168
<DIVIDEND-INCOME>                                         0
<INTEREST-INCOME>                               152,534,834
<OTHER-INCOME>                                            0
<EXPENSES-NET>                                   22,480,263
<NET-INVESTMENT-INCOME>                         130,054,571
<REALIZED-GAINS-CURRENT>                            356,269
<APPREC-INCREASE-CURRENT>                                 0
<NET-CHANGE-FROM-OPS>                           130,410,840
<EQUALIZATION>                                            0
<DISTRIBUTIONS-OF-INCOME>                             7,977
<DISTRIBUTIONS-OF-GAINS>                                  0
<DISTRIBUTIONS-OTHER>                                     0
<NUMBER-OF-SHARES-SOLD>                                   0
<NUMBER-OF-SHARES-REDEEMED>                               0
<SHARES-REINVESTED>                                       0
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<ACCUMULATED-NII-PRIOR>                                   0
<ACCUMULATED-GAINS-PRIOR>                          (527,759)
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<AVERAGE-NET-ASSETS>                                429,983
<PER-SHARE-NAV-BEGIN>                                 1.000
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<RETURNS-OF-CAPITAL>                                  0.000
<PER-SHARE-NAV-END>                                   1.000
<EXPENSE-RATIO>                                        0.50



</TABLE>