WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<RESTATED>
<CIK> 0000860938
<NAME> NUVEEN TAX-FREE UNIT TRUST
<SERIES> Series 607
<NAME> PENNSYLVANIA INSURED TRUST
<NUMBER> 137
<MULTIPLIER> 1
<CURRENCY> U.S. DOLLARS
<FISCAL-YEAR-END> MAR-31-2000
<PERIOD-START> APR-01-1999
<PERIOD-END> MAR-31-2000
<PERIOD-TYPE> YEAR
<EXCHANGE-RATE> 1
<INVESTMENTS-AT-COST> 3,303,851
<INVESTMENTS-AT-VALUE> 3,518,665
<RECEIVABLES> 36,533
<ASSETS-OTHER> 66,606
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 3,621,804
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 809
<TOTAL-LIABILITIES> 809
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 0
<SHARES-COMMON-STOCK> 37,805
<SHARES-COMMON-PRIOR> 38,376
<ACCUMULATED-NII-CURRENT> 65,420
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 75,751
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 214,814
<NET-ASSETS> 3,620,995
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 234,306
<OTHER-INCOME> 0
<EXPENSES-NET> 5,986
<NET-INVESTMENT-INCOME> 228,320
<REALIZED-GAINS-CURRENT> 2,083
<APPREC-INCREASE-CURRENT> -193,718
<NET-CHANGE-FROM-OPS> 36,685
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 232,673
<DISTRIBUTIONS-OF-GAINS> 327,980
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 50,000
<NUMBER-OF-SHARES-REDEEMED> 12,195
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> -579,424
<ACCUMULATED-NII-PRIOR> 69,774
<ACCUMULATED-GAINS-PRIOR> 73,668
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 0
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 0
<AVERAGE-NET-ASSETS> 0
<PER-SHARE-NAV-BEGIN> 0
<PER-SHARE-NII> 0
<PER-SHARE-GAIN-APPREC> 0
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 0
<EXPENSE-RATIO> 0
[AVG-DEBT-OUTSTANDING] 0
[AVG-DEBT-PER-SHARE] 0
</TABLE>
