<ARTICLE>                                           UT
<LEGEND>
THIS SCHEDULE  CONTAINS  FINANCIAL  INFORMATION  EXTRACTED FROM THE DECEMBER 31,
1998 FINANCIAL  STATEMENTS INCLUDED IN THE INTERSTATE ENERGY  CORPORATION'S FORM
10-K AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<CIK>                         0000352541
<NAME>                        INTERSTATE ENERGY CORPOPRATION

<MULTIPLIER>                                   1,000
       
                             
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                              DEC-31-1998
<PERIOD-START>                                 JAN-01-1998
<PERIOD-END>                                   DEC-31-1998
<BOOK-VALUE>                                   PER-BOOK
<TOTAL-NET-UTILITY-PLANT>                      3,101,680
<OTHER-PROPERTY-AND-INVEST>                    1,024,841
<TOTAL-CURRENT-ASSETS>                         387,960
<TOTAL-DEFERRED-CHARGES>                       103,172
<OTHER-ASSETS>                                 341,684
<TOTAL-ASSETS>                                 4,959,337
<COMMON>                                       776
<CAPITAL-SURPLUS-PAID-IN>                      905,130
<RETAINED-EARNINGS>                            700,389 <F1>
<TOTAL-COMMON-STOCKHOLDERS-EQ>                 1,606,295
<PREFERRED-MANDATORY>                          24,396
<PREFERRED>                                    89,102
<LONG-TERM-DEBT-NET>                           1,543,131
<SHORT-TERM-NOTES>                             51,784
<LONG-TERM-NOTES-PAYABLE>                      56,975
<COMMERCIAL-PAPER-OBLIGATIONS>                 64,500
<LONG-TERM-DEBT-CURRENT-PORT>                  63,414
<PREFERRED-STOCK-CURRENT>                      0
<CAPITAL-LEASE-OBLIGATIONS>                    13,755
<LEASES-CURRENT>                               11,978
<OTHER-ITEMS-CAPITAL-AND-LIAB>                 1,434,007
<TOT-CAPITALIZATION-AND-LIAB>                  4,959,337
<GROSS-OPERATING-REVENUE>                      2,130,874
<INCOME-TAX-EXPENSE>                           58,113 <F2>
<OTHER-OPERATING-EXPENSES>                     1,847,572
<TOTAL-OPERATING-EXPENSES>                     1,847,572 <F2>
<OPERATING-INCOME-LOSS>                        283,302
<OTHER-INCOME-NET>                             7,548
<INCOME-BEFORE-INTEREST-EXPEN>                 290,850
<TOTAL-INTEREST-EXPENSE>                       129,363
<NET-INCOME>                                   103,374
<PREFERRED-STOCK-DIVIDENDS>                    6,699
<EARNINGS-AVAILABLE-FOR-COMM>                  96,675
<COMMON-STOCK-DIVIDENDS>                       140,679
<TOTAL-INTEREST-ON-BONDS>                      95,551
<CASH-FLOW-OPERATIONS>                         467,762 
<EPS-PRIMARY>                                  1.26    
<EPS-DILUTED>                                  1.26    
<FN>
<F1> Includes $163,017 of Accumulated Other Comprehensive Income.
<F2> Income tax expense is not included in Operating Expense in the Consolidated
Statements of Income
</FN>