EXHIBIT 3.1


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                            CERTIFICATE OF AMENDMENT



                                     OF THE



                          CERTIFICATE OF INCORPORATION



                                       OF



                        NIAGARA MOHAWK POWER CORPORATION

                UNDER SECTION 805 OF THE BUSINESS CORPORATION LAW

                                  ------------


                                STATE OF NEW YORK
                               DEPARTMENT OF STATE
                            FILED: NOVEMBER 29, 1999
                                   TAX: # NONE



                            DATED: NOVEMBER 29, 1999


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                               SULLIVAN & CROMWELL
                         1701 PENNSYLVANIA AVENUE, N.W.
                           WASHINGTON, D.C. 20006-5805





                            CERTIFICATE OF AMENDMENT

                                     OF THE

                          CERTIFICATE OF INCORPORATION

                                       OF

                        NIAGARA MOHAWK POWER CORPORATION

                UNDER SECTION 805 OF THE BUSINESS CORPORATION LAW
                                   -----------

         Pursuant to the provisions of Section 805 of the BUSINESS CORPORATION
LAW, the undersigned, being the Vice President-Treasurer and the Secretary of
NIAGARA MOHAWK POWER CORPORATION, hereby certify:

                                       I.

         The name of the Corporation is Niagara Mohawk Power Corporation. It was
originally incorporated under the name of Niagara Hudson Public Service
Corporation.

                                       II.

         The Certificate of Consolidation forming the Corporation was filed in
the Department of State on July 31, 1937.

         A Certificate of Change of Name of Niagara Hudson Public Service
Corporation to Central New York Power Corporation was filed in the Department of
State on September 15, 1937.

         A "Certificate of Consolidation of New York Power and Light Corporation
and Buffalo Niagara Electric Corporation and Central New York Power Corporation
into Central New York Power Corporation which is to survive the consolidation
and be named Niagara Mohawk Power Corporation" was filed in the Department of
State on January 5, 1950. Said Certificate of Consolidation is hereinafter
sometimes referred to as the "1950 Certificate of Consolidation".

         Pursuant to Sections 26-a and 36 of the Stock Corporation Law, a
Certificate of Amendment was filed in the Department of State on January 5, 1950
to effect certain changes authorized in subdivision 2 of Section 35 of the Stock
Corporation





Law. Said Certificate of Amendment is hereinafter sometimes referred to as the
"1950 Certificate of Amendment".

         In accordance with the provisions of Subdivision (I) of Paragraph (5)
of Part D of Article IV, under the heading "General Provisions Applicable to All
Series of Preferred Stock", of the 1950 Certificate of Consolidation, the
holders of record of at least a majority of votes which may be cast by the
holders of shares of Preferred Stock of all series then outstanding consented in
writing, as requested by a Consent Statement first mailed by the Corporation on
or about October 28, 1997, to permit the Corporation to incur up to $5 billion
in unsecured indebtedness in excess of the unsecured indebtedness otherwise
permitted by the provisions of Subdivision (E) of Paragraph (5) of Part D of
Article IV of the 1950 Certificate of Amendment, as modified by the resolution
of the holders of Preferred Stock adopted on December 5, 1956.


                                       III

         The Certificate of Incorporation, as heretofore amended, is hereby
further amended by the addition of the following provisions stating the number,
designation, relative rights, preferences, and limitations of a twenty-seventh
additional series of Preferred Stock, to consist of 3,000,000 shares of
Preferred Stock of the Corporation of the par value of $25 per share of the
authorized 19,600,000 shares of Preferred Stock of the Corporation of the par
value of $25 per share, as fixed by the Board of Directors before the issuance
of such series, such provisions so added to be designated as paragraph (4AA) (of
Part D of Article IV of the Certificate of Consolidation as amended by Article V
of the 1950 Certificate of Amendment and subsequent amendments).

Particular Provisions Applicable to FixedAdjustable Rate Cumulative Preferred
Stock, Series D

         (4AA) The number, designation, relative rights, preferences and
limitations of the additional series of Preferred Stock of the Corporation as
fixed by the Board of Directors (in addition to those set forth under the
heading "Provisions Applicable to All Series of Preferred Stock" in Paragraph
(5) of Part D of Article IV of the 1950 Certificate of Consolidation as amended
by Article V of the 1950 Certificate of Amendment and subsequent amendments) are
as follows:

         (A) The number of shares to constitute the twenty-seventh series shall
be 3,000,000 shares, and the designation of such series shall be
"FixedAdjustable Rate Cumulative Preferred Stock, Series D" (hereinafter called,
for purposes of this paragraph 4AA only, the "Series D Preferred Stock").
Defined terms used in this paragraph 4AA shall have the meanings ascribed to
them in this paragraph only for purposes of this paragraph 4AA.





         (B) a. Cumulative cash dividends will be payable on each share of
Series D Preferred Stock when, as, and if declared by the Board of Directors or
a duly authorized committee thereof, out of assets legally available therefor.

         The initial dividend for the dividend period commencing on November 30,
1999 to December 31, 1999 will be $0.2877 per share and will be payable, as if
and when declared by the Board of Directors of the Corporation on December 31,
1999. Thereafter, dividends on the Series D Preferred Stock will be payable
quarterly, as, if and when declared by the Board of Directors of the Corporation
on March 31, June 30, September 30 and December 31 of each year (each a
"Dividend Payment Date") at the annual rate of $3.4525 per share through
December 31, 2004. After December 31, 2004, dividends on the Series D Preferred
Stock will be payable on each Dividend Payment Date, as, if and when declared by
the Board of Directors of the Corporation at the Applicable Rate from time to
time in effect.

         If a Dividend Payment Date is not a business day, dividends (if
declared) on the Series D Preferred Stock will be paid on the next business day,
without interest. Dividends will be payable to holders of record as they appear
on the stock books of the Corporation on the record date fixed by the Board of
Directors of the Corporation, which will not be more than 60 days nor less than
10 days preceding the payment date thereof.

         Accrued but unpaid dividends on the Series D Preferred Stock shall
cumulate as of the Dividend Payment Date on which they first become payable, but
no interest shall accrue on accumulated but unpaid dividends on the Series D
Preferred Stock.

         b. The "Applicable Rate" per annum for each dividend period beginning
after December 31, 2004 will be equal to 1.625% plus the Effective Rate (as
defined below) for such dividend period, but not less than 7.655% nor greater
than 13.655% except as provided below in this paragraph. The "Effective Rate"
for each dividend period beginning after December 31, 2004 will be equal to the
highest of the Treasury Bill Rate, the Ten Year Constant Maturity Rate and the
Thirty Year Constant Maturity Rate (each as defined below) for such dividend
period. In the event that the Corporation determines in good faith that for any
reason: (A) any one of the Treasury Bill Rate, the Ten Year Constant Maturity
Rate or the Thirty Year Constant Maturity Rate cannot be determined for any
dividend period, then the Effective Rate for such dividend period will be equal
to the higher of whichever two of such rates can be so determined; (B) only one
of the Treasury Bill Rate, the Ten Year Constant Maturity Rate or the Thirty
Year Constant Maturity Rate can be determined for any dividend period, then the
Effective Rate for such dividend period will be equal to whichever such rate can
be so determined; or (C) none of the Treasury Bill Rate, the Ten Year Constant
Maturity Rate or the Thirty Year Constant Maturity Rate can be determined for
any dividend period,





then the Effective Rate for the preceding dividend period will be continued for
the succeeding dividend period.

         The "Treasury Bill Rate" will be the arithmetic average of the two most
recent weekly per annum market discount rates (or the one weekly per annum
market discount rate, if only one such rate is published during the relevant
Calendar Period (as defined below)) for three-month U.S. Treasury bills, as
published weekly by the Federal Reserve Board (as defined below) during the
Calendar Period immediately preceding the last ten calendar days preceding the
dividend period for which the dividend rate on the Series D Preferred Stock is
being determined, except as described below in this paragraph. In the event that
the Federal Reserve Board does not publish such a weekly per annum market
discount rate during any such Calendar Period, then the Treasury Bill Rate for
such dividend period will be the arithmetic average of the two most recent
weekly per annum market discount rates (or the one weekly per annum market
discount rate, if only one such rate is published during the relevant Calendar
Period) for three-month U.S. Treasury bills, as published weekly during such
Calendar Period by any Federal Reserve Bank or by any U.S. Government department
or agency selected by the Corporation. In the event that a per annum market
discount rate for three-month U.S. Treasury bills is not published by the
Federal Reserve Board or by any Federal Reserve Bank or by any U.S. Government
department or agency during such Calendar Period, then the Treasury Bill Rate
for such dividend period will be the arithmetic average of the two most recent
weekly per annum market discount rates (or the one weekly per annum market
discount rate, if only one such rate is published during the relevant Calendar
Period) for all of the U.S. Treasury bills then having remaining maturities of
not less than 80 nor more than 100 days, as published during such Calendar
Period by the Federal Reserve Board or, if the Federal Reserve Board does not
publish such rates, by any Federal Reserve Bank or by any U.S. Government
department or agency selected by the Corporation. In the event that the
Corporation determines in good faith that for any reason no such U.S. Treasury
Bill Rates are published as provided above during such Calendar Period, then the
Treasury Bill Rate for such dividend period will be the arithmetic average of
the per annum market discount rates based upon the closing bids during such
Calendar Period for each of the issues of marketable non-interest-bearing U.S.
Treasury securities with a remaining maturity of not less than 80 nor more than
100 days from the date of each such quotation, as chosen and quoted daily for
each business day in New York City (or less frequently if daily quotations are
not generally available) to the Corporation by at least three recognized dealers
in U.S. Government securities selected by the Corporation. In the event that the
Corporation determines in good faith that for any reason the Corporation cannot
determine the Treasury Bill Rate for any dividend period as provided above in
this paragraph, the Treasury Bill Rate for such dividend period will be the
arithmetic average of the per annum market discount rates based upon the closing
bids during such Calendar Period for each of the issues of marketable
interest-bearing U.S. Treasury securities with a remaining maturity of not less
than 80 nor more than 100 days, as chosen and quoted daily for each business day
in New





York City (or less frequently if daily quotations are not generally available)
to the Corporation by at least three recognized dealers in U.S. Government
securities selected by the Corporation.

         The "Ten Year Constant Maturity Rate" will be the arithmetic average of
the two most recent weekly per annum Ten Year Average Yields (as defined below)
(or the one weekly per annum Ten Year Average Yield, if only one such yield is
published during the relevant Calendar Period), as published weekly by the
Federal Reserve Board during the Calendar Period immediately preceding the last
ten calendar days preceding the dividend period for which the dividend rate on
the Series D Preferred Stock is being determined, except as described below in
this paragraph. In the event that the Federal Reserve Board does not publish
such a weekly per annum Ten Year Average Yield during such Calendar Period, then
the Ten Year Constant Maturity Rate for such dividend period will be the
arithmetic average of the two most recent weekly per annum Ten Year Average
Yields (or the one weekly per annum Ten Year Average Yield, if only one such
yield is published during the relevant Calendar Period), as published weekly
during such Calendar Period by any Federal Reserve Bank or by any U.S.
Government department or agency selected by the Corporation. In the event that a
per annum Ten Year Average Yield is not published by the Federal Reserve Board
or by any Federal Reserve Bank or by any U.S. Government department or agency
during such Calendar Period, then the Ten Year Constant Maturity Rate for such
dividend period will be the arithmetic average of the two most recent weekly per
annum average yields to maturity (or the one weekly per annum average yield to
maturity, if only one such yield is published during the relevant Calendar
Period) for all of the actively traded marketable U.S. Treasury fixed interest
rate securities (other than Special Securities (as defined below)) then having
remaining maturities of not less than eight nor more than twelve years, as
published during such Calendar Period by the Federal Reserve Board or, if the
Federal Reserve Board does not publish such yields, by any Federal Reserve Bank
or by any U.S. Government department or agency selected by the Corporation. In
the event that the Corporation determines in good faith that for any reason the
Corporation cannot determine the Ten Year Constant Maturity Rate for any
dividend period as provided above in this paragraph, then the Ten Year Constant
Maturity Rate for such dividend period will be the arithmetic average of the per
annum average yields to maturity based upon the closing bids during such
Calendar Period for each of the issues of actively traded marketable U.S.
Treasury fixed interest rate securities (other than Special Securities) with a
final maturity date not less than eight nor more than twelve years from the date
of each such quotation, as chosen and quoted daily for each business day in New
York City (or less frequently if daily quotations are not generally available)
to the Corporation by at least three recognized dealers in U.S. Government
securities selected by the Corporation.

         The "Thirty Year Constant Maturity Rate" will be the arithmetic average
of the two most recent weekly per annum Thirty Year Average Yields (as defined
below) (or the one weekly per annum Thirty Year Average Yield, if only one such
yield is





published during the relevant Calendar Period), as published weekly by the
Federal Reserve Board during the Calendar Period immediately preceding the
dividend period for which the dividend rate on the Series D Preferred Stock is
being determined except as described below in this paragraph. In the event that
the Federal Reserve Board does not publish such a weekly per annum Thirty Year
Average Yield during such Calendar Period, then the Thirty Year Constant
Maturity Rate for such dividend period will be the arithmetic average of the two
most recent weekly per annum Thirty Year Average Yields (or the one weekly per
annum Thirty Year Average Yield, if only one such yield is published during the
relevant Calendar Period), as published weekly during such Calendar period by
any Federal Reserve Bank or by any U.S. Government department or agency selected
by the Corporation. In the event that a per annum Thirty Year Average Yield is
not published by the Federal Reserve Board or by any Federal Reserve Bank or by
any U.S. Government department or agency during such Calendar Period, then the
Thirty Year Constant Maturity Rate for such dividend period will be the
arithmetic average of the two most recent weekly per annum average yields to
maturity (or the one weekly per annum average yield to maturity, if only one
such yield is published during the relevant Calendar Period) for all of the
actively traded marketable U.S. Treasury fixed interest rate securities (other
than Special Securities) then having remaining maturities of not less than
twenty-eight nor more than thirty years, as published during such Calendar
Period by the Federal Reserve Board or, if the Federal Reserve Board does not
publish such yields, by any Federal Reserve Bank or by any U.S. Government
department or agency selected by the Corporation. In the event that the
Corporation determines in good faith that for any reason the Corporation cannot
determine the Thirty Year Constant Maturity Rate for any applicable dividend
period as provided above in this paragraph, then the Thirty Year Constant
Maturity Rate for such dividend period will be the arithmetic average of the per
annum average yields to maturity based upon the closing bids during such
Calendar Period for each of the issues of actively traded marketable U.S.
Treasury fixed interest rate securities (other than Special Securities) with a
final maturity date not less than twenty-eight nor more than thirty years from
the date of each such quotation, as chosen and quoted daily for each business
day in New York City (or less frequently if daily quotations are not generally
available) to the Corporation by at least three recognized dealers in U.S.
Government securities selected by the Corporation.

         The Treasury Bill Rate, the Ten Year Constant Maturity Rate and the
Thirty Year Constant Maturity Rate will each be rounded to the nearest five
hundredths of a percent.

         The Applicable Rate with respect to each dividend period beginning
after December 31, 2004 will be calculated as promptly as practicable by the
Corporation according to the appropriate method described above. The Corporation
will cause notice of the Applicable Rate for the next dividend period to be
enclosed with the dividend payment to the holders of Series D Preferred Stock.





         As used above, the term "Calendar Period" means a period of fourteen
calendar days; the term "Federal Reserve Board" means the Board of Governors of
the Federal Reserve System; the term "Special Securities" means securities which
can, at the option of the holder, be surrendered at face value in payment of any
Federal estate tax or which provide tax benefits to the holder and are priced to
reflect such tax benefits or which were originally issued at a deep or
substantial discount; the term "Ten Year Average Yield" means the average yield
to maturity for actively traded marketable U.S. Treasury fixed interest rate
securities (adjusted to constant maturities of ten years); and the term "Thirty
Year Average Yield" means the average yield to maturity for actively traded
marketable U.S. Treasury fixed interest rate securities (adjusted to constant
maturities of thirty years).

         c. If, prior to May 30, 2001, one or more amendments to the Internal
Revenue Code of 1986, as amended (the "Code"), are enacted which change the
percentage of the dividends received deduction as specified in Section 243(a)
(1) of the Code or any successor provision (the "Dividends Received
Percentage"), the amount of each dividend on each share of the Series D
Preferred Stock for dividend payments made on or after the date of enactment of
such change will be adjusted by multiplying the amount of the dividend payable
determined as described above (before adjustment) by a factor, which will be the
number determined in accordance with the following formula (the "DRD Formula"),
and rounding the result to the nearest cent:

                               1 - [.35 (1 - .70)]
                           ---------------------------
                               1 - [.35 (1 - DRP)]

         For the purposes of the DRD Formula, "DRP" means the new Dividends
Received Percentage applicable to the dividend in question; provided however,
that if the Dividends Received Percentage applicable to the dividend in question
shall be less than 50%, then the DRP shall equal .50. No amendment to the Code,
other than a change in the percentage of the dividends received deduction set
forth in Section 243(a) (1) of the Code or any successor provision, will give
rise to an adjustment. Notwithstanding the foregoing provisions, in the event
that, with respect to any such amendment, the Corporation shall receive either
an unqualified opinion of nationally recognized independent tax counsel selected
by the Corporation or a private letter ruling or similar form of authorization
from the Internal Revenue Service to the effect that such an amendment does not
apply to dividends payable on the Series D Preferred Stock, then any such
amendment shall not result in the adjustment provided for pursuant to the DRD
Formula. The opinion referenced in the previous sentence must be based upon a
specific exception in the legislation amending the DRP or upon a published
pronouncement of the Internal Revenue Service addressing such legislation.
Unless the context otherwise requires, references to dividends herein shall mean
dividends as adjusted by the DRD Formula. The Corporation's calculation of the
dividends payable as so adjusted and as certified accurate as to calculation and
reasonable as to method by the independent





certified public accountants then regularly engaged by the Corporation, shall be
final and not subject to review.

         If any amendment to the Code which reduces the Dividends Received
Percentage is enacted after a record date and before the next Dividend Payment
Date, the amount of dividend payable on such Dividend Payment Date will not be
increased, but instead, an amount equal to the excess of (x) the product of the
dividends paid by the Corporation on such Dividend Payment Date and the DRD
Formula (where the DRP used in the DRD Formula would be equal to the greater of
the Dividends Received Percentage applicable to the dividend in question and
 .50) over (y) the dividends paid by the Corporation on such Dividend Payment
Date, will be payable (if declared) to holders of record on the next succeeding
Dividend Payment Date in addition to any other amounts payable on such date.

         In addition, if any such amendment to the Code is enacted that reduces
the Dividends Received Percentage and such reduction retroactively applies to a
Dividend Payment Date as to which the Corporation previously paid dividends on
the Series D Preferred Stock (each an "Affected Dividend Payment Date"), the
Corporation will pay (if declared), additional dividends (the "Additional
Dividends") on the next succeeding Dividend Payment Date (or if such amendment
is enacted after the dividend payable on such Dividend Payment Date has been
declared, on the second succeeding Dividend Payment Date following the date of
enactment) to holders of record on such succeeding Dividend Payment Date in an
amount equal to the excess of (x) the product of the dividends paid by the
Corporation on each Affected Dividend Payment Date and the DRD Formula (where
the DRP used in the DRD Formula would be equal to the greater of the Dividends
Received Percentage and .50 applied to each Affected Dividend Payment Date) over
(y) the dividends paid by the Corporation on each Affected Dividend Payment
Date.

         Notwithstanding the foregoing, Additional Dividends will not be paid as
a result of the enactment of any amendment to the Code 18 months or more after
the date of original issuance of the Series D Preferred Stock which
retroactively reduces the Dividends Received Percentage, or if such amendment
would not result in an adjustment due to the Corporation having received either
an opinion of counsel or tax ruling referred to in the third preceding
paragraph. The Corporation will make only one payment of Additional Dividends.

         In the event that the amount of dividend payable per share of the
Series D Preferred Stock will be adjusted pursuant to the DRD Formula and/or
Additional Dividends are to be paid, the Corporation will cause notice of each
such adjustment and, if applicable, any Additional Dividends, to be sent to the
holders of the Series D Preferred Stock with the payment of dividends on the
next Dividend Payment Date after the date of such adjustment.





         (C) In the event of any voluntary or involuntary liquidation,
dissolution or winding up of the Corporation, the holders of shares of Series D
Preferred Stock will be entitled to receive out of the assets of the Corporation
available for distribution to stockholders, before any distribution of assets is
made on the Corporation's Common Stock or any other class or series of stock of
the Corporation ranking junior to the Series D Preferred Stock upon liquidation,
liquidating distributions in the amount of $50 per share, plus an amount equal
to the sum of all accrued and unpaid dividends including any increase in
dividends payable due to changes in the Dividends Received Percentage and
Additional Dividends (whether or not earned or declared) for the then current
dividend period and all dividend periods prior thereto.

         (D) Except as provided under the heading "Provisions Applicable to All
Series of Preferred Stock" in Paragraph (5) of Part D of Article IV of the 1950
Certificate of Consolidation as amended by Article V of the 1950 Certificate of
Amendment and subsequent amendments, the Series D Preferred Stock shall have no
voting rights whatsoever.

         (E) Prior to December 31, 2004, the Series D Preferred Stock is not
redeemable. On or after such date, each share of Series D Preferred Stock will
be redeemable, in whole or in part at the option of the Corporation at any time
and from time to time upon not less than thirty nor more than sixty days'
notice, at a redemption price of $50 per share, together in each case with
accrued and unpaid dividends (whether or not declared) to the date fixed for
redemption including any increase in dividends payable due to changes in the
Dividends Received Percentage and Additional Dividends. If fewer than all the
outstanding shares of Series D Preferred Stock are to be redeemed, the
Corporation will select those to be redeemed by lot or pro rata or by any other
method as may be determined by the Board of Directors to be equitable, and such
redemption shall otherwise be in the manner prescribed under the heading
"Provisions Applicable to All Series of Preferred Stock" in Paragraph (5) of
Part D of Article IV of the 1950 Certificate of Consolidation as amended by
Article V of the 1950 Certificate of Amendment and subsequent amendments.

         (F) Shares of Series D Preferred Stock redeemed, purchased or otherwise
acquired by the Corporation shall be cancelled and restored to the status of
authorized but unissued shares of Preferred Stock of the par value $25 per share
without serial designation and may be reissued by the Corporation from time to
time as Preferred Stock of any other series of the par value of $25 per share as
may be fixed from time to time by the Board of Directors.

         (G) The shares of the Series D Preferred Stock shall be subject to the
consent set forth in the last subparagraph of Paragraph II of this Certificate
to the same





extent and with the same effect as all series of Preferred Stock outstanding on
October 28, 1997 are so subject.


                                       IV

         The amendments of the Certificate of Incorporation effected by this
Certificate were authorized by action of the Board of Directors of the
Corporation, pursuant to Section 502 of the Business Corporation Law.


         IN WITNESS WHEREOF, we have made and subscribed this Certificate this
23rd day of November, 1999.


                                        By:/s/ Arthur W. Roos
                                           ------------------------------------
                                           Name:  Arthur W. Roos
                                           Title: Vice President-Treasurer


                                        By:/s/ Kapua A. Rice
                                           ------------------------------------
                                           Name:  Kapua A. Rice
                                           Title: Secretary


[Corporate Seal]





STATE OF NEW YORK                   )
                                    :  ss.:
COUNTY OF ONODAGA                   )

                  Arthur W. Roos, being duly sworn, deposes and says that
he is Vice President-Treasurer of Niagara Mohawk Power Corporation, the
corporation named in and described in the foregoing Certificate, that he has
read and executed the foregoing Certificate and knows the contents thereof and
that the statements contained therein are true.


                                        By:/s/ Arthur W. Roos
                                           ------------------------------------
                                           Name:  Arthur W. Roos
                                           Title: Vice President-Treasurer


                                        By:/s/ Kapua A. Rice
                                           ------------------------------------
                                           Name:  Kapua A. Rice
                                           Title: Secretary

Sworn to before me this
23rd day of November, 1999


/s/ Kapua A. Rice
- --------------------------
Notary Public