<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0001083536
<NAME> MUNIHOLDINGS INSURED FUND III, INC.
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> APR-30-2000
<PERIOD-START> MAY-28-1999
<PERIOD-END> APR-30-2000
<INVESTMENTS-AT-COST> 156212093
<INVESTMENTS-AT-VALUE> 151145565
<RECEIVABLES> 6968388
<ASSETS-OTHER> 76639
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 158190592
<PAYABLE-FOR-SECURITIES> 3872440
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 338192
<TOTAL-LIABILITIES> 4210632
<SENIOR-EQUITY> 67850000
<PAID-IN-CAPITAL-COMMON> 101215927
<SHARES-COMMON-STOCK> 6806667
<SHARES-COMMON-PRIOR> 6667
<ACCUMULATED-NII-CURRENT> 554586
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (10574025)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> (5066528)
<NET-ASSETS> 153979960
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 8137732
<OTHER-INCOME> 0
<EXPENSES-NET> (552172)
<NET-INVESTMENT-INCOME> 7585560
<REALIZED-GAINS-CURRENT> (10574025)
<APPREC-INCREASE-CURRENT> (5066528)
<NET-CHANGE-FROM-OPS> (8054993)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (4880509)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 6800000
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 153879955
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 778334
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 1134695
<AVERAGE-NET-ASSETS> 152786371
<PER-SHARE-NAV-BEGIN> 15.00
<PER-SHARE-NII> 1.12
<PER-SHARE-GAIN-APPREC> (2.30)
<PER-SHARE-DIVIDEND> (.72)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> (.03)
<PER-SHARE-NAV-END> 12.65
<EXPENSE-RATIO> 0.80
</TABLE>