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SIGNATURE JOHN J. ARTHUR
TITLE SR VP & TREASURER
WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
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<PAYABLE-FOR-SECURITIES> 34963751
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 2167800
<TOTAL-LIABILITIES> 37131551
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 424032642
<SHARES-COMMON-STOCK> 41631965
<SHARES-COMMON-PRIOR> 39326428
<ACCUMULATED-NII-CURRENT> 59434
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (3605851)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 2146223
<NET-ASSETS> 422632448
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 11380508
<OTHER-INCOME> 0
<EXPENSES-NET> (1113649)
<NET-INVESTMENT-INCOME> 10266859
<REALIZED-GAINS-CURRENT> 1870966
<APPREC-INCREASE-CURRENT> 1445705
<NET-CHANGE-FROM-OPS> 13583530
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (10296267)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 31456871
<NUMBER-OF-SHARES-REDEEMED> (29914190)
<SHARES-REINVESTED> 762856
<NET-CHANGE-IN-ASSETS> 26667901
<ACCUMULATED-NII-PRIOR> 88842
<ACCUMULATED-GAINS-PRIOR> (5476817)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 431775
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1113649
<AVERAGE-NET-ASSETS> 386461670
<PER-SHARE-NAV-BEGIN> 10.07
<PER-SHARE-NII> .24
<PER-SHARE-GAIN-APPREC> .08
<PER-SHARE-DIVIDEND> (.24)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 10.15
<EXPENSE-RATIO> .54
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information from the AIM
Limited Maturity Treasury Fund Institutional Class semi-annual report.
</LEGEND>
<CIK> 0000842790
<NAME> AIM INVESTMENT SECURITIES FUNDS
<SERIES>
<NUMBER> 2
<NAME> AIM LIMITED MATURITY TREASURY FUND INSTITUTIONAL CLASS
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> JUL-31-1999
<PERIOD-END> JAN-31-1999
<INVESTMENTS-AT-COST> 414559460
<INVESTMENTS-AT-VALUE> 416705683
<RECEIVABLES> 42541758
<ASSETS-OTHER> 103340
<OTHER-ITEMS-ASSETS> 413218
<TOTAL-ASSETS> 459763999
<PAYABLE-FOR-SECURITIES> 34963751
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 2167800
<TOTAL-LIABILITIES> 37131551
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 424032642
<SHARES-COMMON-STOCK> 41631965
<SHARES-COMMON-PRIOR> 39326428
<ACCUMULATED-NII-CURRENT> 59434
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (3605851)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 2146223
<NET-ASSETS> 422632448
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 11380508
<OTHER-INCOME> 0
<EXPENSES-NET> (1113649)
<NET-INVESTMENT-INCOME> 10266859
<REALIZED-GAINS-CURRENT> 1870966
<APPREC-INCREASE-CURRENT> 1445705
<NET-CHANGE-FROM-OPS> 13583530
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (10296267)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 31456871
<NUMBER-OF-SHARES-REDEEMED> (29914190)
<SHARES-REINVESTED> 762856
<NET-CHANGE-IN-ASSETS> 26667901
<ACCUMULATED-NII-PRIOR> 88842
<ACCUMULATED-GAINS-PRIOR> (5476817)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 431775
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1113649
<AVERAGE-NET-ASSETS> 41793488
<PER-SHARE-NAV-BEGIN> 10.07
<PER-SHARE-NII> .25
<PER-SHARE-GAIN-APPREC> .08
<PER-SHARE-DIVIDEND> (.25)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 10.15
<EXPENSE-RATIO> .31
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
