<ARTICLE> UT
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM
THE CONSOLIDATED BALANCE SHEET, CONSOLIDATED STATEMENT OF INCOME,
AND CONSOLIDATED STATEMENT OF CASH FLOWS OF NIAGARA MOHAWK POWER
CORPORATION AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO
SUCH FINANCIAL STATEMENTS.
</LEGEND>
<CIK> 0000071932
<NAME> NIAGARA MOHAWK POWER CORPORATION
<MULTIPLIER> 1000

                             
<PERIOD-TYPE>                   YEAR
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-END>                               DEC-31-1999
<BOOK-VALUE>                                  PER-BOOK
<TOTAL-NET-UTILITY-PLANT>                      5888242
<OTHER-PROPERTY-AND-INVEST>                     349718
<TOTAL-CURRENT-ASSETS>                          585978
<TOTAL-DEFERRED-CHARGES>                       5517786
<OTHER-ASSETS>                                  103884
<TOTAL-ASSETS>                                12445608
<COMMON>                                        187365
<CAPITAL-SURPLUS-PAID-IN>                      2355986
<RETAINED-EARNINGS>                             398987
<TOTAL-COMMON-STOCKHOLDERS-EQ>                 2785171
<PREFERRED-MANDATORY>                            61370
<PREFERRED>                                     440000
<LONG-TERM-DEBT-NET>                           5042588
<SHORT-TERM-NOTES>                                   0
<LONG-TERM-NOTES-PAYABLE>                            0
<COMMERCIAL-PAPER-OBLIGATIONS>                       0
<LONG-TERM-DEBT-CURRENT-PORT>                   613740
<PREFERRED-STOCK-CURRENT>                         7620
<CAPITAL-LEASE-OBLIGATIONS>                          0
<LEASES-CURRENT>                                     0
<OTHER-ITEMS-CAPITAL-AND-LIAB>                 3495119
<TOT-CAPITALIZATION-AND-LIAB>                 12445608
<GROSS-OPERATING-REVENUE>                      3827340
<INCOME-TAX-EXPENSE>                             18883
<OTHER-OPERATING-EXPENSES>                     3295789
<TOTAL-OPERATING-EXPENSES>                     3295789
<OPERATING-INCOME-LOSS>                         531551
<OTHER-INCOME-NET>                              (5682)
<INCOME-BEFORE-INTEREST-EXPEN>                  525869
<TOTAL-INTEREST-EXPENSE>                        485240
<NET-INCOME>                                    (2061)
<PREFERRED-STOCK-DIVIDENDS>                      36808
<EARNINGS-AVAILABLE-FOR-COMM>                  (38869)
<COMMON-STOCK-DIVIDENDS>                             0
<TOTAL-INTEREST-ON-BONDS>                            0
<CASH-FLOW-OPERATIONS>                          798730
<EPS-BASIC>                                        0
<EPS-DILUTED>                                        0