WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000866700
<NAME> Federated Municipal Securities Income Trust
<SERIES>
<NUMBER> 042
<NAME> California Municipal Income Fund - Class B Shares
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> Aug-31-2000
<PERIOD-END> Aug-31-2000
<INVESTMENTS-AT-COST> 57,751,311
<INVESTMENTS-AT-VALUE> 59,275,041
<RECEIVABLES> 898,438
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 153,403
<TOTAL-ASSETS> 60,326,882
<PAYABLE-FOR-SECURITIES> 126,876
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 158,031
<TOTAL-LIABILITIES> 284,907
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 61,651,882
<SHARES-COMMON-STOCK> 3,434,178
<SHARES-COMMON-PRIOR> 3,393,659
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (3,133,637)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1,523,730
<NET-ASSETS> 36,576,994
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 3,315,641
<OTHER-INCOME> 0
<EXPENSES-NET> (563,222)
<NET-INVESTMENT-INCOME> 2,752,419
<REALIZED-GAINS-CURRENT> (1,922,128)
<APPREC-INCREASE-CURRENT> 2,607,096
<NET-CHANGE-FROM-OPS> 3,437,387
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (1,530,476)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 828,977
<NUMBER-OF-SHARES-REDEEMED> (875,128)
<SHARES-REINVESTED> 86,670
<NET-CHANGE-IN-ASSETS> (3,605,985)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (1,211,509)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 237,130
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1,052,228
<AVERAGE-NET-ASSETS> 35,226,724
<PER-SHARE-NAV-BEGIN> 10.490
<PER-SHARE-NII> 0.450
<PER-SHARE-GAIN-APPREC> 0.160
<PER-SHARE-DIVIDEND> (0.450)
<PER-SHARE-DISTRIBUTIONS> 0.000
<RETURNS-OF-CAPITAL> 0.000
<PER-SHARE-NAV-END> 10.650
<EXPENSE-RATIO> 1.25
[AVG-DEBT-OUTSTANDING] 0
[AVG-DEBT-PER-SHARE] 0.000
</TABLE>
