<ARTICLE> UT
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE JUNE 30,
1998 FINANCIAL STATEMENTS INCLUDED IN INTERSTATE ENERGY CORPORATION'S FORM 10-Q
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<CIK>   0000352541
<NAME>  INTERSTATE ENERGY CORPORATION
<MULTIPLIER> 1,000
       
                             
<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>                  1,109,481
<TOTAL-CURRENT-ASSETS>                         364,315
<TOTAL-DEFERRED-CHARGES>                        91,771
<OTHER-ASSETS>                                 326,635
<TOTAL-ASSETS>                               4,949,319
<COMMON>                                           769
<CAPITAL-SURPLUS-PAID-IN>                      881,734
<RETAINED-EARNINGS>                            777,305<F1>
<TOTAL-COMMON-STOCKHOLDERS-EQ>               1,659,808
<PREFERRED-MANDATORY>                           24,331
<PREFERRED>                                     89,102
<LONG-TERM-DEBT-NET>                         1,489,369
<SHORT-TERM-NOTES>                              35,324
<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>               1,414,225
<TOT-CAPITALIZATION-AND-LIAB>                4,949,319
<GROSS-OPERATING-REVENUE>                    1,047,295
<INCOME-TAX-EXPENSE>                            19,124<F2>
<OTHER-OPERATING-EXPENSES>                     934,588
<TOTAL-OPERATING-EXPENSES>                     934,588<F2>
<OPERATING-INCOME-LOSS>                        112,707
<OTHER-INCOME-NET>                             (4,018)
<INCOME-BEFORE-INTEREST-EXPEN>                 108,689
<TOTAL-INTEREST-EXPENSE>                        63,155
<NET-INCOME>                                    26,410
<PREFERRED-STOCK-DIVIDENDS>                      3,349
<EARNINGS-AVAILABLE-FOR-COMM>                   23,061
<COMMON-STOCK-DIVIDENDS>                        79,455
<TOTAL-INTEREST-ON-BONDS>                       92,333
<CASH-FLOW-OPERATIONS>                         218,211
<EPS-PRIMARY>                                     0.30
<EPS-DILUTED>                                     0.30
<FN>
<F1>Includes $215,039 of accumulated other comprehensive income.
<F2>Income tax expense is not included in Operating Expenses in the Consolidated
Statements of Income.
</FN>