<TABLE> <S> <C>

<ARTICLE>                                           UT
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE JUNE 30,
1998 FINANCIAL  STATEMENTS OF INTERSTATE ENERGY  CORPORATION AND IS QUALIFIED IN
ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS. CERTAIN ADJUSTMENTS HAVE
BEEN MADE TO THE PRIOR PERIOD AMOUNTS AS PART OF THE  RESTATEMENT TO REFLECT THE
CHANGE IN ACCOUNTING METHOD FOR OIL AND GAS PROPERTIES FROM THE FULL COST METHOD
TO THE SUCCESSFUL EFFORTS METHOD.
</LEGEND>
<RESTATED>
<CIK>      0000352541
<NAME>     INTERSTATE ENERGY CORPORATION
<MULTIPLIER>     1,000
                                     
<S>                             <C>  
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                                         DEC-31-1998
<PERIOD-START>                                            JAN-01-1998
<PERIOD-END>                                              JUN-30-1998
<BOOK-VALUE>                                                 PER-BOOK
<TOTAL-NET-UTILITY-PLANT>                                   3,057,117
<OTHER-PROPERTY-AND-INVEST>                                 1,074,216
<TOTAL-CURRENT-ASSETS>                                        364,315
<TOTAL-DEFERRED-CHARGES>                                       91,771
<OTHER-ASSETS>                                                326,635
<TOTAL-ASSETS>                                              4,914,054
<COMMON>                                                          769
<CAPITAL-SURPLUS-PAID-IN>                                     881,734
<RETAINED-EARNINGS>                                           752,543 <F1>
<TOTAL-COMMON-STOCKHOLDERS-EQ>                              1,635,046
<PREFERRED-MANDATORY>                                          24,331
<PREFERRED>                                                    89,102
<LONG-TERM-DEBT-NET>                                        1,489,369
<SHORT-TERM-NOTES>                                             36,324
<LONG-TERM-NOTES-PAYABLE>                                      56,975
<COMMERCIAL-PAPER-OBLIGATIONS>                                 77,651
<LONG-TERM-DEBT-CURRENT-PORT>                                  68,985
<PREFERRED-STOCK-CURRENT>                                           0
<CAPITAL-LEASE-OBLIGATIONS>                                    19,338
<LEASES-CURRENT>                                               13,211
<OTHER-ITEMS-CAPITAL-AND-LIAB>                              1,403,722
<TOT-CAPITALIZATION-AND-LIAB>                               4,914,054
<GROSS-OPERATING-REVENUE>                                   1,047,295
<INCOME-TAX-EXPENSE>                                           16,208 <F2>
<OTHER-OPERATING-EXPENSES>                                    940,788
<TOTAL-OPERATING-EXPENSES>                                    940,788 <F2>
<OPERATING-INCOME-LOSS>                                       106,507
<OTHER-INCOME-NET>                                             (4,018)
<INCOME-BEFORE-INTEREST-EXPEN>                                102,489
<TOTAL-INTEREST-EXPENSE>                                       63,155
<NET-INCOME>                                                   23,126
<PREFERRED-STOCK-DIVIDENDS>                                     3,349
<EARNINGS-AVAILABLE-FOR-COMM>                                  19,777
<COMMON-STOCK-DIVIDENDS>                                       63,649
<TOTAL-INTEREST-ON-BONDS>                                      92,333
<CASH-FLOW-OPERATIONS>                                        221,328
<EPS-PRIMARY>                                                    0.26
<EPS-DILUTED>                                                    0.26
<FN>
<F1> Includes $215,039 of Accumulated Other Comprehensive Income.

<F2> Income tax expense is not included in Operating Expense in the Consolidated
Statements of Income.
</FN>
                                               


</TABLE>