<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000862501
<NAME> SALOMON BROTHERS INSTITUTIONAL SERIES FUNDS
<SERIES>
   <NUMBER> 1
   <NAME> INSTITUTIONAL HIGH YIELD BOND FUND

<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          FEB-28-2000
<PERIOD-END>                               AUG-31-1999
<INVESTMENTS-AT-COST>                       43,246,605
<INVESTMENTS-AT-VALUE>                      39,689,385
<RECEIVABLES>                                  798,082
<ASSETS-OTHER>                                  24,579
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                              40,512,046
<PAYABLE-FOR-SECURITIES>                             0
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                       13,232
<TOTAL-LIABILITIES>                             13,232
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                    42,999,463
<SHARES-COMMON-STOCK>                        4,789,243
<SHARES-COMMON-PRIOR>                        4,346,436
<ACCUMULATED-NII-CURRENT>                    2,212,374
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                    (1,155,803)
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                   (3,557,220)
<NET-ASSETS>                                40,498,814
<DIVIDEND-INCOME>                                    0
<INTEREST-INCOME>                            1,922,405
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                 107,753
<NET-INVESTMENT-INCOME>                      1,814,652
<REALIZED-GAINS-CURRENT>                     (424,571)
<APPREC-INCREASE-CURRENT>                  (2,055,707)
<NET-CHANGE-FROM-OPS>                        (665,626)
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                            0
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                        442,807
<NUMBER-OF-SHARES-REDEEMED>                          0
<SHARES-REINVESTED>                                  0
<NET-CHANGE-IN-ASSETS>                       3,132,221
<ACCUMULATED-NII-PRIOR>                        397,722
<ACCUMULATED-GAINS-PRIOR>                    (731,232)
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                            9,787
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                164,054
<AVERAGE-NET-ASSETS>                        38,454,347
<PER-SHARE-NAV-BEGIN>                             8.60
<PER-SHARE-NII>                                   0.41
<PER-SHARE-GAIN-APPREC>                         (0.55)
<PER-SHARE-DIVIDEND>                                 0
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                               8.46
<EXPENSE-RATIO>                                   0.55


</TABLE>