<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000027825
<NAME> DELAWARE GROUP INCOME FUNDS
<SERIES>
<NUMBER> 054
<NAME> DELAWARE EXTENDED DURATION BOND FUND INSTITUTIONAL
CLASS
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> JUL-31-1999
<PERIOD-END> JAN-31-2000
<INVESTMENTS-AT-COST> 69,991,459
<INVESTMENTS-AT-VALUE> 66,098,263
<RECEIVABLES> 3,079,853
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 27,689
<TOTAL-ASSETS> 69,205,805
<PAYABLE-FOR-SECURITIES> 2,448,764
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 0
<TOTAL-LIABILITIES> 2,448,764
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 73,421,489
<SHARES-COMMON-STOCK> 12,940,280
<SHARES-COMMON-PRIOR> 10,798,890
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (2,702,501)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> (3,961,947)
<NET-ASSETS> 64,545,052
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 2,313,897
<OTHER-INCOME> 0
<EXPENSES-NET> 165,392
<NET-INVESTMENT-INCOME> 2,148,505
<REALIZED-GAINS-CURRENT> (838,300)
<APPREC-INCREASE-CURRENT> (922,455)
<NET-CHANGE-FROM-OPS> 387,750
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 2,085,185
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 12,583,775
<NUMBER-OF-SHARES-REDEEMED> 2,452,517
<SHARES-REINVESTED> 327,043
<NET-CHANGE-IN-ASSETS> 9,911,444
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 160,975
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 298,157
<AVERAGE-NET-ASSETS> 120,611
<PER-SHARE-NAV-BEGIN> 5.500
<PER-SHARE-NII> 0.212
<PER-SHARE-GAIN-APPREC> (0.216)
<PER-SHARE-DIVIDEND> 0.212
<PER-SHARE-DISTRIBUTIONS> 0.004
<RETURNS-OF-CAPITAL> 0.000
<PER-SHARE-NAV-END> 5.280
<EXPENSE-RATIO> 0.550
</TABLE>
