<Page>
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MARCH 19, 2003
                                                      REGISTRATION NO. 333-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

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

                                    FORM S-3

                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

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

                   NEW YORK STATE ELECTRIC & GAS CORPORATION
             (Exact name of registrant as specified in its charter)

<Table>
                                                       
                        NEW YORK                                                 15-0398550
            (State or other jurisdiction of                       (I.R.S. Employer Identification Number)
             incorporation or organization)
</Table>

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

                                 P.O. BOX 3287
                          ITHACA, NEW YORK 14852-3287
                                 (607) 347-4131
    (Address, including zip code, and telephone number, including area code,
                of the registrant's principal executive offices)

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

<Table>
                                                       
                    RALPH R. TEDESCO                                          FRANK LEE, ESQ.
         President and Chief Operating Officer                             Huber Lawrence & Abell
       New York State Electric & Gas Corporation                              605 Third Avenue
                     P.O. Box 3287                                           New York, NY 10158
                 Ithaca, NY 14852-3287                                         (212) 682-6200
                     (607) 347-4131
</Table>

 (Names, addresses, including zip codes, and telephone numbers, including area
                         codes, of agents for service)

    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:  From time
to time after the effective date of this registration statement.

    If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box. / /

    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, please check the following box. /X/

    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. / /

    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /

    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. / /

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

                        CALCULATION OF REGISTRATION FEE

<Table>
<Caption>
                                                          PROPOSED MAXIMUM     PROPOSED MAXIMUM
                                        AMOUNT TO BE     OFFERING PRICE PER   AGGREGATE OFFERING        AMOUNT OF
TITLE OF SECURITIES TO BE REGISTERED     REGISTERED            UNIT(1)            PRICE(1)(2)       REGISTRATION FEE
                                                                                       
New York State Electric & Gas
 Corporation Senior Unsecured Debt
 Securities and New Preferred
 Stock..............................    $300,000,000            100%             $300,000,000            $24,270
</Table>

(1) Estimated solely for the purpose of calculating the registration fee.

(2) Exclusive of accrued interest, if any.

    PURSUANT TO RULE 429 UNDER THE SECURITIES ACT OF 1933, THE PROSPECTUS
INCLUDED IN THIS REGISTRATION STATEMENT IS A COMBINED PROSPECTUS WHICH ALSO
RELATES TO REGISTRATION STATEMENT NO. 33-50719, PREVIOUSLY FILED BY NEW YORK
STATE ELECTRIC & GAS CORPORATION ON FORM S-3, UNDER WHICH $50,000,000 OF
SECURITIES REMAINS UNISSUED. THIS REGISTRATION STATEMENT ALSO CONSTITUTES A
POST-EFFECTIVE AMENDMENT TO REGISTRATION STATEMENT NO. 33-50719, AND SUCH
POST-EFFECTIVE AMENDMENT SHALL HEREAFTER BECOME EFFECTIVE CONCURRENTLY WITH THE
EFFECTIVENESS OF THIS REGISTRATION STATEMENT IN ACCORDANCE WITH SECTION 8(C) OF
THE SECURITIES ACT OF 1933.

    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT FILES
A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION STATEMENT
WILL THEN BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF THE SECURITIES ACT
OF 1933 OR UNTIL THIS REGISTRATION STATEMENT BECOMES EFFECTIVE ON SUCH DATE AS
THE SECURITIES AND EXCHANGE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<Page>
                  SUBJECT TO COMPLETION, DATED MARCH 19, 2003
THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE MAY
NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER
TO SELL THESE SECURITIES AND WE ARE NOT SOLICITING AN OFFER TO BUY THESE
SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.
<Page>
PROSPECTUS

                                  $350,000,000
                   NEW YORK STATE ELECTRIC & GAS CORPORATION
                        SENIOR UNSECURED DEBT SECURITIES
                                PREFERRED STOCK

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

    This prospectus contains summaries of the general terms of these securities.
We will provide the specific terms of these securities, and the manner in which
they are being offered, in supplements to this prospectus. You should read this
prospectus and the applicable prospectus supplement carefully before you invest.

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

    NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
REGULATOR HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

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

    This prospectus may not be used to sell securities unless accompanied by a
prospectus supplement. Any statement contained in this prospectus will be deemed
to be modified or superseded by any inconsistent statement contained in an
accompanying prospectus supplement.

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

               The date of this prospectus is             , 2003.
<Page>
                               TABLE OF CONTENTS

<Table>
<Caption>
                                                                PAGE
                                                              --------
                                                           
ABOUT THIS PROSPECTUS.......................................      3
WHERE YOU CAN FIND MORE INFORMATION.........................      3
CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS...      5
NEW YORK STATE ELECTRIC & GAS CORPORATION...................      6
USE OF PROCEEDS.............................................      6
RATIO OF EARNINGS TO FIXED CHARGES AND RATIO OF EARNINGS TO
  FIXED CHARGES AND PREFERRED STOCK DIVIDENDS...............      6
DESCRIPTION OF SECURITIES...................................      7
  Senior Unsecured Debt Securities..........................      7
  New Preferred Stock.......................................     15
PLAN OF DISTRIBUTION........................................     18
EXPERTS.....................................................     19
LEGAL MATTERS...............................................     19
</Table>

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

    In this prospectus, references to "we," "us" and "our" refer to New York
State Electric & Gas Corporation.

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

                                       2
<Page>
                             ABOUT THIS PROSPECTUS

    This prospectus is part of a registration statement registering $300,000,000
of securities that we filed with the SEC utilizing a "shelf" registration
process. This prospectus also relates to a shelf registration statement that we
filed previously with the SEC under which $50,000,000 of securities remained
unissued. Under this shelf registration process, any combination of the
securities described in this prospectus may be sold from time to time in one or
more offerings of one or more series up to a total dollar amount of
$350,000,000. This prospectus only provides you with a general description of
the securities that may be offered. Each time securities are sold, a "prospectus
supplement" will be provided which will contain specific information about the
terms of that offering. Material United States federal income tax considerations
applicable to the offered securities will also be discussed in the applicable
prospectus supplement.

    A prospectus supplement may also add, update or change information contained
in this prospectus. You should read both this prospectus and any prospectus
supplement together with additional information described under the heading
WHERE YOU CAN FIND MORE INFORMATION.

    We believe that we have included or incorporated by reference in this
prospectus all information material to investors, but certain details that may
be important for specific investment purposes have not been included. For more
detail, you should read the exhibits filed with or incorporated by reference
into the registration statement.

                      WHERE YOU CAN FIND MORE INFORMATION

AVAILABLE INFORMATION

    We file annual, quarterly and current reports. You may read and copy this
information at the SEC's public reference rooms at:

<Table>
                                            
            Public Reference Room                         Midwest Regional Office
                  Room 1024                                   Citicorp Center
               Judiciary Plaza                                  Suite 1400
           450 Fifth Street, N.W.                         500 West Madison Street
            Washington, DC 20549                          Chicago, IL 60661-2511
</Table>

    You may call the SEC at 1-800-SEC-0330 for further information on the public
reference rooms. Our SEC filings are also available to the public from
commercial document retrieval services and at the Internet world wide website
that the SEC maintains at HTTP://WWW.SEC.GOV.

    This prospectus is part of a registration statement that we filed with the
SEC. The full registration statement may be obtained from the SEC or us, as
indicated below. Documents and forms of documents establishing certain of the
terms of the offered securities are filed as exhibits to the registration
statement. Statements in this prospectus about these documents are summaries.
You should refer to the actual documents for a more complete description of the
relevant matters.

INCORPORATION BY REFERENCE

    The SEC allows us to "incorporate by reference" information into this
document, which means that we can disclose important information to you by
referring you to another document filed separately with the SEC. The information
incorporated by reference is deemed to be part of this prospectus. The
information filed with the SEC in the future will automatically update and
supersede this information.

                                       3
<Page>
    We incorporate by reference the documents listed below and any future
filings made by us with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the
Securities Exchange Act of 1934, until all of the securities being offered under
this prospectus or any prospectus supplement are sold:

    - Our Annual Report on Form 10-K for the year ended December 31, 2002.

    Documents incorporated by reference are available from us without charge,
excluding all exhibits unless we have specifically incorporated by reference an
exhibit into this prospectus. You may obtain documents incorporated by reference
in this prospectus by writing or telephoning:

                   NEW YORK STATE ELECTRIC & GAS CORPORATION
                              Shareholder Services
                                 P.O. Box 3200
                          Ithaca, New York 14852-3200
                                 (800) 225-5643

    YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED OR INCORPORATED BY
REFERENCE IN THIS PROSPECTUS OR ANY PROSPECTUS SUPPLEMENT. WE HAVE NOT
AUTHORIZED ANYONE TO PROVIDE YOU WITH DIFFERENT INFORMATION. WE ARE NOT MAKING
AN OFFER OF THESE SECURITIES IN ANY STATE WHERE THE OFFER IS NOT PERMITTED. YOU
SHOULD NOT ASSUME THAT THE INFORMATION CONTAINED IN THIS PROSPECTUS OR ANY
PROSPECTUS SUPPLEMENT IS ACCURATE AS OF ANY DATE OTHER THAN THE DATE OF SUCH
DOCUMENTS.

                                       4
<Page>
           CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

    This prospectus, any accompanying prospectus supplement and the additional
information described under the heading WHERE YOU CAN FIND MORE INFORMATION may
contain some forward-looking statements that involve risks and uncertainties. We
may make these statements about our financial condition, results of operations
and business. These statements may be made directly in this prospectus, or may
be "incorporated by reference" from other documents filed with the SEC. You can
find many of these statements by looking for words such as "believes,"
"expects," "anticipates," "estimates" or similar expressions. These
forward-looking statements are subject to numerous assumptions, risks and
uncertainties. Factors that may cause actual results to differ from those
indicated by such forward-looking statements, include, among others, the
following:

    - the deregulation and continued regulatory unbundling of a vertically
      integrated industry;

    - our ability to compete in the rapidly changing and increasingly
      competitive electricity and natural gas utility markets;

    - regulatory uncertainty in a politically-charged environment of changing
      energy prices;

    - operation of the New York Independent System Operator;

    - operation of a regional transmission organization;

    - our ability to recover nonutility generator and other costs;

    - changes in fuel supply or cost and the success of strategies to satisfy
      power requirements now that most generation assets have been sold;

    - our ability to expand our products and services;

    - market risk;

    - our ability to obtain adequate and timely rate relief;

    - environmental incidents;

    - legal or administrative proceedings;

    - changes in the cost or availability of capital;

    - the effect of the volatility in the equity markets on pension benefit
      cost;

    - growth in the areas in which we are doing business;

    - weather variations affecting customer energy usage;

    - authoritative accounting guidance;

    - acts of terrorists; and

    - other considerations that may be disclosed from time to time in our
      publicly disseminated documents or filings.

    You should not place undue reliance on the forward-looking statements, which
speak only as of the date of this prospectus or any prospectus supplement or, in
the case of a document incorporated by reference, the date of that document.

    The cautionary statements in this section expressly qualify, in their
entirety, all subsequent forward-looking statements attributable to us or any
person acting on our behalf. We do not undertake any obligation to release
publicly any revisions to the forward-looking statements to reflect events or
circumstances occurring after the date of this prospectus, any prospectus
supplement or any document incorporated by reference.

                                       5
<Page>
                   NEW YORK STATE ELECTRIC & GAS CORPORATION

    We are a public utility company engaged in transmitting and distributing
electricity and transporting, storing and distributing natural gas.
Approximately 82% of our operating revenues for 2002, 2001 and 2000 was derived
from electricity deliveries, with the balance each year derived from natural gas
deliveries.

    Our service territory, 99% of which is located outside the corporate limits
of cities, is in the central, eastern and western parts of the State of New
York. Our service territory has an area of approximately 20,000 square miles and
a population of 2,500,000. The larger cities in New York in which we serve both
electricity and natural gas customers are Binghamton, Elmira, Auburn, Geneva,
Ithaca and Lockport. We provide delivery service to approximately 838,000
electricity customers and 250,000 natural gas customers. The service territory
reflects a diversified economy, including high-tech firms, light industry,
colleges and universities, agriculture, and recreational facilities. No customer
accounts for more than 5% of either of our electric or natural gas revenues.

    We were organized under the laws of the State of New York in 1852. In May
1998, we became a subsidiary of Energy East Corporation, a public utility
holding company that was organized under the laws of the State of New York.
Energy East is a super-regional energy services and delivery company with
operations in New York, Connecticut, Massachusetts, Maine and New Hampshire and
corporate offices in New York and Maine. In connection with Energy East's merger
with RGS Energy Group, Inc. in June 2002, RGS Energy became a wholly-owned
subsidiary of Energy East and we became a wholly-owned subsidiary of RGS Energy.

    Our address is P.O. Box 3287, Ithaca, New York 14852-3287 and our telephone
number is (607) 347-4131.

                                USE OF PROCEEDS

    We intend to use the net proceeds from the sale of the securities for
general corporate purposes, which may include, among other things, the
retirement or repurchase of certain of our indebtedness or preferred stock,
reduction of short-term debt, financing the development and construction of new
facilities and additions to working capital.

 RATIO OF EARNINGS TO FIXED CHARGES AND RATIO OF EARNINGS TO FIXED CHARGES AND
                           PREFERRED STOCK DIVIDENDS

    The following table sets forth our ratio of earnings to fixed charges and
our ratio of earnings to fixed charges and preferred stock dividends for the
five most recent fiscal years:

<Table>
<Caption>
                                                                            YEAR ENDED DECEMBER 31,
                                                              ----------------------------------------------------
                                                                2002       2001       2000       1999       1998
                                                              --------   --------   --------   --------   --------
                                                                                           
Ratio of earnings to fixed charges (1)......................    3.36       4.33       4.41       4.48       3.81
Ratio of earnings to fixed charges and preferred stock
  dividends (1).............................................    3.33       4.30       4.39       4.30       3.44
</Table>

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

(1) The ratio of earnings to fixed charges is calculated by dividing earnings by
    fixed charges. The ratio of earnings to fixed charges and preferred stock
    dividends is calculated by dividing earnings by fixed charges and preferred
    stock dividends. For this purpose earnings means income before income taxes
    and fixed charges. Fixed charges means all interest charges and the interest
    component of rentals.

                                       6
<Page>
                           DESCRIPTION OF SECURITIES

SENIOR UNSECURED DEBT SECURITIES

    The following description sets forth the general terms and provisions of the
senior unsecured debt securities that we may offer by this prospectus.

    We will issue the senior unsecured debt securities under an unsecured debt
indenture between us and JPMorgan Chase Bank, as unsecured debt indenture
trustee. The unsecured debt indenture gives us broad authority to set the
particular terms of each series of senior unsecured debt securities, including
the right to modify certain of the terms contained in the unsecured debt
indenture. The particular terms of a series of senior unsecured debt securities
and the extent, if any, to which the particular terms of the issue modify the
terms of the unsecured debt indenture will be described in the prospectus
supplement relating to the senior unsecured debt securities.

    The unsecured debt indenture contains the full text of the matters described
in this section. Because this section is a summary, it does not describe every
aspect of the senior unsecured debt securities or the unsecured debt indenture.
This summary is subject to and qualified in its entirety by reference to all the
provisions of the unsecured debt indenture, including definitions of terms used
in that indenture, which is filed as an exhibit to the registration statement,
of which this prospectus forms a part and is incorporated by reference. We also
include references in parentheses to certain sections of the unsecured debt
indenture. Whenever we refer to particular sections or defined terms of the
unsecured debt indenture in this prospectus or in a prospectus supplement, these
sections or defined terms are incorporated by reference herein or in the
prospectus supplement. This summary also is subject to and qualified by
reference to the description of the particular terms of the senior unsecured
debt securities described in the applicable prospectus supplement or
supplements.

    Prospective purchasers of senior unsecured debt securities should be aware
that special U.S. federal income tax, accounting and other considerations may be
applicable to the senior unsecured debt securities of a particular series. The
prospectus supplement relating to an issue of senior unsecured debt securities
will describe these considerations, if they apply.

    There is no requirement under the unsecured debt indenture that future
issues of our senior unsecured debt securities be issued under that indenture.
We will be free to use other indentures or documentation, containing provisions
different from those included in the unsecured debt indenture or applicable to
one or more issues of senior unsecured debt securities, in connection with
future issues of other debt securities.

GENERAL

    The unsecured debt indenture does not limit the aggregate principal amount
of senior unsecured debt securities that we may issue under that indenture. The
unsecured debt indenture provides that the senior unsecured debt securities may
be issued in one or more series. The senior unsecured debt securities may be
issued at various times and may have differing maturity dates and may bear
interest at differing rates. We need not issue all senior unsecured debt
securities of one series at the same time and, unless otherwise provided, we may
reopen a series, without the consent of the holders of the senior unsecured debt
securities of that series, for issuances of additional senior unsecured debt
securities of that series.

    Prior to the issuance of each series of senior unsecured debt securities,
the particular terms will be specified in a supplemental indenture, a board
resolution or in one or more officer's certificates

                                       7
<Page>
authorized pursuant to a board resolution. We refer you to the applicable
prospectus supplement for a description of the following terms of the series of
senior unsecured debt securities:

    - title of the senior unsecured debt securities;

    - any limit on the aggregate principal amount of the senior unsecured debt
      securities;

    - the person to whom any interest on the senior unsecured debt securities
      shall be payable, if other than the person in whose name those securities
      are registered at the close of business on the regular record date;

    - the date or dates on which the principal of the senior unsecured debt
      securities will be payable or how the date or dates will be determined;

    - the rate or rates at which the senior unsecured debt securities will bear
      interest, or how the rate or rates will be determined and the date or
      dates from which interest will accrue;

    - the dates on which interest will be payable;

    - the record dates for payments of interest;

    - the place or places, if any, in addition to the office of the unsecured
      debt indenture trustee, where the principal of, and premium, if any, and
      interest, if any, on the senior unsecured debt securities will be payable;

    - the period or periods within which, the price or prices at which, and the
      terms and conditions upon which, the senior unsecured debt securities may
      be repaid, in whole or in part, at the option of the holder thereof;

    - any sinking fund or other provisions or options held by holders of the
      senior unsecured debt securities that would obligate us to repurchase or
      redeem those securities;

    - the percentage, if less than 100%, of the principal amount of the senior
      unsecured debt securities that will be payable if the maturity of those
      securities is accelerated;

    - any changes or additions to the events of default under the unsecured debt
      indenture or changes or additions to our covenants under that indenture;
      and

    - any other specific terms applicable to the senior unsecured debt
      securities.

    Unless we otherwise indicate in the applicable prospectus supplement, the
senior unsecured debt securities will be denominated in United States currency
in minimum denominations of $1,000 and multiples of $1,000.

    Unless we otherwise indicate in the applicable prospectus supplement, there
are no provisions in the unsecured debt indenture or the senior unsecured debt
securities that require us to redeem, or permit the holders to cause a
redemption of, the senior unsecured debt securities or that otherwise protect
the holders in the event that we incur substantial additional indebtedness.

SECURITY AND RANKING

    The senior unsecured debt securities issued by us will be our unsecured
obligations and will rank equally with all of our other unsecured and
unsubordinated debt.

                                       8
<Page>
PAYMENT AND PAYING AGENTS

    Unless otherwise indicated in the applicable prospectus supplement, we will
pay interest on our senior unsecured debt securities on each interest payment
date by check mailed to the person in whose name that security is registered as
of the close of business on the regular record date relating to the interest
payment date, except that interest payable at stated maturity, upon redemption
or otherwise, will be paid to the person to whom principal is paid. However, if
we default in paying interest on a senior unsecured debt security, we will pay
defaulted interest to the registered owner of that security in one of the
following ways:

    - we will first propose to the unsecured debt indenture trustee a payment
      date for the defaulted interest. Next, the unsecured debt indenture
      trustee will choose a special record date for determining which registered
      holders are entitled to the payment. The special record date will be
      between 10 and 15 days before the payment date we propose. Finally, we
      will pay the defaulted interest on the payment date to the registered
      holder of the senior unsecured debt security as of the close of business
      on the special record date; or

    - we can propose to the unsecured debt indenture trustee any other lawful
      manner of payment that is consistent with the requirements of any
      securities exchange on which the senior unsecured debt securities may be
      listed for trading. If the unsecured debt indenture trustee thinks the
      proposal is practicable, payment will be made as proposed.

REDEMPTION

    We will set forth any terms for the redemption of senior unsecured debt
securities in a prospectus supplement. Unless we indicate differently in the
applicable prospectus supplement, and except with respect to senior unsecured
debt securities redeemable at the option of the registered holder, senior
unsecured debt securities will be redeemable upon notice by mail between 30 and
60 days prior to the redemption date. If less than all of the senior unsecured
debt securities of any series or any tranche of a series are to be redeemed, the
unsecured debt indenture trustee will select the senior unsecured debt
securities to be redeemed and will choose the method of random selection it
deems fair and appropriate (See sections 301, 1103 and 1104 of the unsecured
debt indenture.)

    Senior unsecured debt securities will cease to bear interest on the
redemption date. We will pay the redemption price and any accrued interest to
the redemption date once you surrender those securities for redemption. (See
section 1106 of the unsecured debt indenture.) If only part of a senior
unsecured debt security is redeemed, the unsecured debt indenture trustee will
deliver to you a new senior unsecured debt security of the same series for the
remaining portion without charge. (See section 1107 of the unsecured debt
indenture.)

    We may make any redemption conditional upon the receipt by the paying agent,
on or prior to the date fixed for redemption, of money sufficient to pay the
redemption price. If the paying agent has not received the money by the date
fixed for redemption, we will not be required to redeem the senior unsecured
debt securities. (See section 1104 of the unsecured debt indenture.)

REGISTRATION, TRANSFER, EXCHANGE AND FORM

    Unless otherwise indicated in the applicable prospectus supplement, the
senior unsecured debt securities will be issued only in fully registered form,
without interest coupons and in denominations that are even multiples of $1,000.
Senior unsecured debt securities of any series will be exchangeable for other
senior unsecured debt securities of the same series of any authorized
denominations and of a like aggregate principal amount and tenor. (See
section 305 of the unsecured debt indenture.)

    Unless we otherwise indicate in the applicable prospectus supplement, senior
unsecured debt securities may be presented for registration of transfer, duly
endorsed or accompanied by a duly executed written instrument of transfer, at
the office or agency maintained for such purpose, without

                                       9
<Page>
service charge except for reimbursement of taxes and other governmental charges
as described in the unsecured debt indenture. (See section 305 of the unsecured
debt indenture.)

    In the event of any redemption of senior unsecured debt securities of any
series, the unsecured debt indenture trustee will not be required to exchange or
register a transfer of any senior unsecured debt securities of the series
selected, called or being called for redemption except the unredeemed portion of
any senior unsecured debt security being redeemed in part. (See section 305 of
the unsecured debt indenture.)

BOOK-ENTRY ONLY SYSTEM

    The following discussion pertains to senior unsecured debt securities that
are issued in book-entry only form.

    One or more global notes would be issued to DTC, The Depository Trust
Company, or its nominee. DTC would keep a computerized record of its
participants (for example, your broker) whose clients have purchased the senior
unsecured debt securities. The participant would then keep a record of its
clients who purchased those securities. A global note may not be transferred,
except that DTC, its nominees and their successors may transfer an entire global
note to one another.

    Under book-entry only, we will not issue certificates to individual holders
of the senior unsecured debt securities. Beneficial interests in global notes
will be shown on, and transfers of beneficial interests in global notes will be
made only through, records maintained by DTC and its participants.

    DTC has advised us that it is:

    - a limited-purpose trust company organized under the New York Banking Law;

    - a "banking organization" within the meaning of the New York Banking Law;

    - a member of the Federal Reserve System;

    - a "clearing corporation" within the meaning of the New York Uniform
      Commercial Code; and

    - a "clearing agency" registered pursuant to the provisions of Section 17A
      of the Securities Exchange Act of 1934.

    DTC holds securities that its participants deposit with DTC. DTC also
facilitates the settlement among direct participants of securities transactions,
such as transfers and pledges, in deposited securities through computerized
records for direct participants' accounts. This eliminates the need to exchange
certificates. Direct participants include securities brokers and dealers, banks,
trust companies, clearing corporations and certain other organizations.

    DTC's book-entry system is also used by other organizations such as
securities brokers and dealers, banks and trust companies that work through a
direct participant. The rules that apply to DTC and its participants are on file
with the SEC.

    DTC is owned by a number of its direct participants and by the New York
Stock Exchange, Inc., the American Stock Exchange, Inc. and the National
Association of Securities Dealers, Inc.

    We will wire principal and interest payments to DTC's nominee. We and the
unsecured debt indenture trustee will treat DTC's nominee as the owner of the
global notes for all purposes. Accordingly, we and the unsecured debt indenture
trustee will have no direct responsibility or liability to pay amounts due on
the senior unsecured debt securities to owners of beneficial interests in the
global notes.

    It is DTC's current practice, upon receipt of any payment of principal or
interest, to credit direct participants' accounts on the payment date according
to their respective holdings of beneficial interests in the global notes as
shown on DTC's records as of the record date for such payment. In addition, it
is DTC's current practice to assign any consenting or voting rights to direct
participants whose accounts

                                       10
<Page>
are credited with securities on a record date, by using an omnibus proxy.
Payments by participants to owners of beneficial interests in the global notes,
and voting by participants, will be governed by the customary practices between
the participants and owners of beneficial interests, as is the case with
securities held for the account of customers registered in "street name."
However, these payments will be the responsibility of the participants and not
of DTC, the unsecured debt indenture trustee, or us.

    Senior unsecured debt securities represented by a global note will be
exchangeable for senior unsecured debt securities certificates with the same
terms in authorized denominations only if:

    - DTC notifies us that it is unwilling or unable to continue as depository
      or if DTC ceases to be a clearing agency registered under applicable law;

    - we instruct the unsecured debt indenture trustee that the global note is
      now exchangeable; or

    - an event of default has occurred and is continuing.

    According to DTC, the foregoing information with respect to DTC has been
provided to the financial community for informational purposes only and is not
intended to serve as a representation, warranty, or contract modification of any
kind.

CONSOLIDATION, MERGER, CONVEYANCE, SALE OR TRANSFER

    Unless otherwise indicated in the applicable prospectus supplement, we have
agreed not to consolidate with or merge into any other entity or convey,
transfer, or lease our properties and assets substantially as an entirety to any
entity unless:

    - the successor is an entity organized and existing under the laws of the
      United States of America or any state or the District of Columbia;

    - the successor expressly assumes by a supplemental indenture the due and
      punctual payment of the principal of, and premium, if any, and interest on
      all the outstanding senior unsecured debt securities and the performance
      of every covenant of the unsecured debt indenture that we would otherwise
      have to perform; and

    - immediately after giving effect to the transactions, no event of default
      and no event which after notice or lapse of time or both would become an
      event of default, will have occurred and be continuing. (See section 801
      of the unsecured debt indenture.)

MODIFICATION OF THE UNSECURED DEBT INDENTURE

    Under the unsecured debt indenture or any supplemental indenture, our rights
and the rights of the holders of senior unsecured debt securities may be changed
with the consent of the holders representing a majority in principal amount of
the outstanding senior unsecured debt securities of all series affected by the
change, voting as one class, provided that the following changes may not be made
without the consent of the holders of each outstanding senior unsecured debt
security affected thereby:

    - change the fixed date upon which the principal of or the interest on any
      senior unsecured debt security is due and payable, or reduce the principal
      amount thereof or the rate of interest thereon or any premium payable upon
      the redemption thereof, or reduce the amount of the principal of an
      original issue discount security that would be payable upon a declaration
      of acceleration of the maturity thereof, or change any place of payment
      where, or the currency in which, any senior unsecured debt security or
      premium, if any, or the interest thereon is payable, or impair the right
      to institute suit for the enforcement of any payment on or after the date
      such payment is due or, in the case of redemption, on or after the date
      fixed for such redemption;

                                       11
<Page>
    - reduce the stated percentage of senior unsecured debt securities of any
      series, the consent of the holders of which is required for any
      modification of the unsecured debt indenture or for waiver by the holders
      of certain of their rights; or

    - modify certain provisions of the unsecured debt indenture. (See
      section 902 of the unsecured debt indenture.)

    An original issue discount senior unsecured debt security means any security
authenticated and delivered under the unsecured debt indenture which provides
for an amount less than the principal amount thereof to be due and payable upon
the declaration of acceleration of the maturity thereof.

    The unsecured debt indenture also contains provisions permitting us and the
unsecured debt indenture trustee to amend that indenture in certain
circumstances without the consent of the holders of any senior unsecured debt
securities to evidence a merger, the replacement of the unsecured debt indenture
trustee and for certain other purposes. (See section 901 of the unsecured debt
indenture.)

EVENTS OF DEFAULT

    An event of default with respect to any series of senior unsecured debt
securities is defined in the unsecured debt indenture as being any one of the
following:

    - failure to pay interest on the senior unsecured debt securities of that
      series for 30 days after payment is due;

    - failure to pay principal or any premium on the senior unsecured debt
      securities of that series when due;

    - failure to perform other covenants in the unsecured debt indenture for
      60 days after we are given written notice from the unsecured debt
      indenture trustee or the unsecured debt indenture trustee receives written
      notice from the registered owners of at least 25% in principal amount of
      the senior unsecured debt securities of that series;

    - failure to pay any sinking fund installment on the senior unsecured debt
      securities when due;

    - default occurs under any bond, note, debenture or other instrument
      evidencing any indebtedness for money borrowed by us (including a default
      with respect to any other series of senior unsecured debt securities
      issued under the unsecured debt indenture), or under any mortgage,
      indenture or other instrument under which there may be issued or by which
      there may be secured or evidenced any indebtedness for money borrowed by
      us (or the payment of which is guaranteed by us), whether such
      indebtedness or guarantee exists on the date of the unsecured debt
      indenture or is issued or entered into following the date of the unsecured
      debt indenture, if:

       - either:

           - such default results from failure to pay any such indebtedness when
             due; or

           - as a result of such default the maturity of such indebtedness has
             been accelerated prior to its expressed maturity; and

       - the principal amount of such indebtedness, together with the principal
         amount of any other such indebtedness in default for failure to pay any
         such indebtedness when due or the maturity of which has been so
         accelerated, aggregates at least $40 million; and

    - certain events of bankruptcy, insolvency, reorganization, receivership or
      liquidation relating to us. (See section 501 of the unsecured debt
      indenture.)

                                       12
<Page>
    An event of default regarding a particular series of senior unsecured debt
securities does not necessarily constitute an event of default for any other
series of senior unsecured debt securities.

    We will be required to file with the unsecured debt indenture trustee
annually an officer's certificate as to the absence of default in performance of
certain covenants in the unsecured debt indenture. (See section 1007 of the
unsecured debt indenture.) The unsecured debt indenture provides that the
unsecured debt indenture trustee may withhold notice to the holders of the
senior unsecured debt securities of any default, except in payment of principal
of, or premium, if any, or interest on, those securities or in the payment of
any sinking fund installment with respect to those securities, if the unsecured
debt indenture trustee in good faith determines that it is in the interest of
the holders of those securities to do so. (See section 602 of the unsecured debt
indenture.)

    The unsecured debt indenture provides that, if an event of default with
respect to the senior unsecured debt securities specified therein shall have
happened and be continuing, either the unsecured debt indenture trustee or the
holders of 25% or more in aggregate principal amount of the senior unsecured
debt securities may declare the principal amount of all the senior unsecured
debt securities to be due and payable immediately. However, if all defaults are
cured or waived and certain other conditions are met, such declaration may be
annulled and past defaults may be waived by the holders of a majority in
aggregate principal amount of the senior unsecured debt securities of the
affected series. (See section 502 of the unsecured debt indenture.)

    Subject to the provisions of the unsecured debt indenture relating to the
duties of the unsecured debt indenture trustee, the unsecured debt indenture
trustee will be under no obligation to exercise any of its rights or powers
under that indenture at the request or direction of any of the holders of the
senior unsecured debt securities, unless the holders shall have offered to the
unsecured debt indenture trustee reasonable indemnity. (See section 603 of the
unsecured debt indenture.)

    Subject to the provision for indemnification, the holders of a majority in
principal amount of the senior unsecured debt securities will have the right to
direct the time, method and place of conducting any proceeding for any remedy
available to the unsecured debt indenture trustee, or exercising any trust or
power conferred on that indenture trustee with respect to the senior unsecured
debt securities. However, the unsecured debt indenture trustee shall have the
right to decline to follow any direction if that trustee shall determine that
the action so directed conflicts with any law or the provisions of the unsecured
debt indenture or if that trustee shall determine that the action would be
prejudicial to holders not taking part in the direction. (See section 512 of the
unsecured debt indenture.)

DEFEASANCE

    The unsecured debt indenture provides, unless otherwise indicated in the
applicable prospectus supplement with respect to a particular series of senior
unsecured debt securities, that we may elect either (a) to be discharged from
all of our obligations with respect to the senior unsecured debt securities of
any series, except for obligations to register the transfer or exchange of
senior unsecured debt securities, replace stolen, lost or mutilated senior
unsecured debt securities, to maintain paying agencies and to hold moneys for
payment in trust which we refer to as "DEFEASANCE," or (b) to be released from
our obligations under sections of the unsecured debt indenture described under
"--CONSOLIDATION, MERGER, CONVEYANCE, SALE OR TRANSFER" or to certain covenants
relating to corporate existence and maintenance of properties and insurance, in
each case, which we refer to as "COVENANT DEFEASANCE," if:

    - we deposit with the unsecured debt indenture trustee, in trust, money, or
      in certain cases, U.S. government obligations sufficient to pay and
      discharge (i) the principal of, and premium, if any, and interest, if any,
      on the outstanding senior unsecured debt securities on the dates such
      payments are due, in accordance with the terms of those securities and
      (ii) any mandatory sinking fund payments applicable to the senior
      unsecured debt securities on the day on which

                                       13
<Page>
      payments are due and payable in accordance with the terms of the unsecured
      debt indenture and of those securities;

    - no event of default or event which with notice or lapse of time would
      become an event of default, including by reason of such deposit, with
      respect to the senior unsecured debt securities shall have occurred and be
      continuing on the date of such deposit;

    - we deliver to the unsecured debt indenture trustee an opinion of counsel
      to the effect that the holders will not recognize income, gain or loss for
      federal income tax purposes as a result of such deposit and defeasance of
      certain obligations; and

    - we have delivered to the unsecured debt indenture trustee an officers'
      certificate and an opinion of counsel, each stating that all conditions
      precedent provided for in the unsecured debt indenture relating to the
      satisfaction and discharge of the senior unsecured debt securities have
      been complied with. (See sections 403 and 1008 of the unsecured debt
      indenture.)

    Discharged means, with respect to the senior unsecured debt securities of
any series, the discharge of the entire indebtedness represented by, and our
obligations under, the senior unsecured debt securities of such series and in
the satisfaction of all of our obligations under the unsecured debt indenture
relating to the senior unsecured debt securities of such series, except:

    - the rights of holders of the senior unsecured debt securities of such
      series to receive, from the trust fund established pursuant to the
      unsecured debt indenture, payment of the principal of and interest and
      premium, if any, on the senior unsecured debt securities of such series
      when such payments are due;

    - our obligations with respect to the senior unsecured debt securities of
      such series with respect to registration, transfer, exchange and
      maintenance of a place of payment;

    - the rights, powers, trusts, duties, protections and immunities of the
      unsecured debt indenture trustee under the unsecured debt indenture; and

    - our obligations with respect to the unsecured debt indenture trustee. (See
      section 101 of the unsecured debt indenture.)

    If we have deposited or caused to be deposited money or U.S. government
obligations to pay or discharge the principal of, and premium, if any, and
interest, if any, on the outstanding senior unsecured debt securities to and
including a redemption date on which all of the outstanding senior unsecured
debt securities are to be redeemed, such redemption date shall be irrevocably
designated by a board of directors resolution delivered to the unsecured debt
indenture trustee on or prior to the date of deposit of such money or U.S.
government obligations, and such board of directors resolution shall be
accompanied by an irrevocable company request that the unsecured debt indenture
trustee give notice of such redemption in our name and at our expense not less
than 30 nor more than 60 days prior to such redemption date in accordance with
the unsecured debt indenture. (See section 403 of the unsecured debt indenture.)

    U.S. government obligations means direct obligations of the United States
for the payment of which its full faith and credit is pledged, or obligations of
a person controlled or supervised by and acting as an agency or instrumentality
of the United States and the payment of which is unconditionally guaranteed by
the United States. U.S. government obligations shall also include a depositary
receipt issued by a bank or trust company as custodian with respect to any such
U.S. government obligation or a specific payment of interest on or principal of
any such U.S. government obligation held by such custodian for the account of a
holder of a depositary receipt. However, except as required by law, such
custodian is not authorized to make any deduction from the amount payable to the
holder of such depositary receipt from any amount received by the custodian in
respect of the U.S. government

                                       14
<Page>
obligation or the specific payment of interest on or principal of the U.S.
government obligation evidenced by such depositary receipt. (See section 101 of
the unsecured debt indenture.)

RESIGNATION OR REMOVAL OF UNSECURED DEBT INDENTURE TRUSTEE

    The unsecured debt indenture trustee may resign at any time by giving
written notice to us specifying the day upon which the resignation is to take
effect. The resignation will take effect immediately upon the later of the
appointment of a successor unsecured debt indenture trustee and such specified
day. (See section 610 of the unsecured debt indenture.)

    The unsecured debt indenture trustee may be removed at any time with respect
to the senior unsecured debt securities of any series by an instrument or
concurrent instruments in writing delivered to the unsecured debt indenture
trustee and us and signed by the holders, or their attorneys-in-fact,
representing at least a majority in principal amount of the then outstanding
debt securities of that series. In addition, under certain circumstances, we may
remove the unsecured debt indenture trustee upon notice to the holder of each
senior unsecured debt security outstanding and the unsecured debt indenture
trustee, and appointment of a successor unsecured debt indenture trustee. (See
section 610 of the unsecured debt indenture.)

CONCERNING THE UNSECURED DEBT INDENTURE TRUSTEE

    JPMorgan Chase Bank is the trustee under the unsecured debt indenture.
JPMorgan Chase Bank also serves as the mortgage trustee under the mortgage with
respect to the first mortgage bonds issued by us. We and our affiliates maintain
other banking relationships in the ordinary course of business with the
unsecured debt indenture trustee and its affiliates, including utilizing its
services for the making of short-term loans.

GOVERNING LAW

    The unsecured debt indenture is governed by, and the senior unsecured debt
securities will be governed by, and construed in accordance with the laws of the
State of New York.

NEW PREFERRED STOCK

    The following description sets forth the general terms and provisions of the
new preferred stock that we may offer by this prospectus.

    We will issue the new preferred stock subject to our Restated Certificate of
Incorporation, as amended, and the applicable Certificate of Amendment of the
Restated Certificate of Incorporation of New York State Electric & Gas
Corporation pursuant to Section 805 of the Business Corporation Law ("805
CERTIFICATE"). The particular terms of a series of new preferred stock will be
described in the prospectus supplement relating to the new preferred stock. When
we refer to preferred stock, such term includes preferred stock we previously
have issued and the new preferred stock.

    Our charter and the applicable 805 Certificate set forth the designations,
preferences, privileges and voting powers of the shares of the new preferred
stock. Because this section is a summary, it does not describe every aspect of
the new preferred stock. This summary is subject to and qualified in its
entirety by reference to all the provisions of the charter and the applicable
805 Certificate, including definitions of terms used in the charter and the 805
Certificate, both of which are filed as an exhibit to the registration
statement, of which this prospectus forms a part and are incorporated by
reference. This summary is also subject to and qualified by reference to the
description of the particular terms of the new preferred stock described in the
applicable prospectus supplement or supplements.

    Prospective purchasers of new preferred stock should be aware that special
U.S. federal income tax, accounting and other considerations may be applicable
to the new preferred stock of a particular

                                       15
<Page>
series. The prospectus supplement relating to an issue of new preferred stock
will describe these considerations, if they apply.

DIVIDEND RIGHTS

    The holders of the new preferred stock are entitled to receive, and will be
limited to, when and as declared by the Board of Directors, out of surplus
legally available for the payment of dividends, cumulative preferential
dividends in cash, as specified in the applicable prospectus supplement, payable
quarterly on the first day of January, April, July and October, cumulative from
the date of issue. The date that the initial dividend on the new preferred stock
is expected to be payable and the record date for such dividend are set forth in
the applicable prospectus supplement.

    In case the stated dividends are not paid in full, the shares of all series
of the preferred stock shall share ratably in the payment of dividends,
including accumulations, if any, in accordance with the sums which would be
payable on those shares if all dividends were declared and paid in full.

LIMITATION ON THE PAYMENT OF DIVIDENDS

    There are no limitations on the payment of dividends on the preferred stock.

    Unless dividends on all outstanding shares of preferred stock for all past
quarterly dividend periods shall have been paid and the full dividend thereon
for the then current quarterly dividend period shall have been paid or declared
and funds set apart for payment, no dividends shall be paid or declared, and no
other distribution shall be made, on any of our preference stock or common stock
or on any other class of stock having no preferences or having preferences
ranking in all respects junior to the preferences of the preferred stock and no
such stock shall be purchased, retired or otherwise acquired by us.

VOTING RIGHTS

    If preferred stock dividends on any series are in default in an amount
equivalent to four full quarterly dividends, the holders of the preferred stock,
voting separately as a class without regard to series, are entitled to elect a
majority of the Board of Directors and their privilege continues until all
dividends in default have been paid. The holders of preferred stock are not
entitled to vote in respect of any other matters except those, if any, in
respect of which voting rights cannot be denied or waived under some mandatory
provision of law, and except that the Restated Certificate of Incorporation, as
amended, contains provisions to the effect that such holders shall be entitled
to vote on certain matters affecting the rights and preferences of the preferred
stock relating to (1) an increase in the authorized number of shares of
preferred stock; (2) consolidation or sale of all or substantially all of our
property or assets unless ordered or approved by the Securities and Exchange
Commission; (3) issuance or assumption of any securities representing unsecured
indebtedness in excess of a certain amount (in addition to certain unsecured
indebtedness excluded under consents obtained from holders of the preferred
stock); (4) changes in provisions of the preferred stock; (5) authorization of
stock ranking superior to the preferred stock; (6) change of stock ranking
junior to the preferred stock into shares ranking on a parity with or superior
to the preferred stock; (7) reduction of capital allocable to the outstanding
preferred stock; or reduction below $22,000,000 of the capital allocable to all
stock ranking junior to the preferred stock, unless required or permitted by a
regulatory body and (8) issuance of any shares of preferred stock if the
aggregate par value of shares at any one time outstanding, exceeds $15,000,000,
or any shares of any class of stock ranking superior to, or on a parity with,
the preferred stock, unless, for a period of 12 consecutive months within the
15 months immediately preceding the month in which such additional shares shall
be issued, our net earnings as defined in the Restated Certificate of
Incorporation, as amended, permit such issue. A majority vote of the preferred
stock is

                                       16
<Page>
required with respect to (1), (2) and (3) above and a two-thirds vote with
respect to (4), (5), (6), (7) and (8) above.

    Whenever holders of preferred stock shall be entitled, as a class, to vote,
consent or otherwise act, they shall be entitled to cast one-quarter of one vote
for each share of preferred stock with a par value of $25 per share, and one
vote for each share of preferred stock with a par value of $100 per share, held
by them respectively.

REDEMPTION PROVISIONS

    Redemption provisions for the new preferred stock will be set forth in the
applicable prospectus supplement.

SINKING FUND PROVISIONS

    Sinking fund provisions, if any, for the new preferred stock will be set
forth in the applicable prospectus supplement.

LIQUIDATION RIGHTS

    In the event we voluntarily or involuntarily liquidate, dissolve or wind-up
our company, the holders of each series of preferred stock will be entitled to
receive, and will be limited to, the amount or amounts payable in cash (not less
than the par value thereof plus all dividends accumulated and unpaid thereon)
fixed for such series before any amount may be paid to, or assets distributed
among, holders of stock ranking junior to the preferred stock. The amount per
share payable on the new preferred stock in the event that we voluntarily
liquidate, dissolve or wind-up our company shall be the amount per share at
which such shares could be redeemed (other than through a sinking fund, if any)
as set forth in the applicable prospectus supplement. The amount per share
payable on such new preferred stock in the event of any involuntary liquidation,
dissolution or winding-up shall be the par value thereof, together in each case
with an amount equal to accrued unpaid dividends to the date of such
liquidation, dissolution or winding-up.

LIABILITY FOR FURTHER CALLS OR ASSESSMENTS

    The new preferred stock, when duly issued, will be fully paid and
non-assessable.

PREEMPTIVE RIGHTS

    No holder of any series of preferred stock will be entitled of right, upon
any issue for money or other consideration of stock, or of obligations
convertible into stock, to subscribe for, purchase or receive any such stock or
obligations.

OTHER PROVISIONS

    So long as senior securities (including the new preferred stock) are
outstanding, cash dividends can be paid on common stock only out of earned
surplus accumulated since December 31, 1946. Such dividends are limited to 75%
of net income available for common stock if common stock equity falls below 25%
of total capitalization, and to 50% if common stock equity falls below 20%. Our
common stock equity at December 31, 2002 was approximately 48% of total
capitalization as defined in the 805 Certificate. We have not been restricted in
the payment of dividends on common stock by these provisions and do not believe
that we will be so restricted in the future.

                                       17
<Page>
CONCERNING THE TRANSFER AGENT AND REGISTRAR

    The transfer agent and registrar for the new preferred stock is Mellon
Investor Services LLC, P.O. Box 3315, South Hackensack, NJ 07606-1915.

                              PLAN OF DISTRIBUTION

    We may use the following methods to sell the securities:

    - through negotiation with one or more underwriters;

    - through one or more agents or dealers designated from time to time;

    - directly to purchasers; or

    - through any combination of the above.

The distribution of the securities may be effected from time to time in one or
more transactions at a fixed price or prices which may be changed, at market
prices prevailing at the time of sale, at prices related to such prevailing
market prices or at negotiated prices. A prospectus supplement or a supplement
thereto will describe the method of distribution of any series of securities.

    If we use any underwriters in the sale of securities, we will enter into an
underwriting agreement, distribution agreement or similar agreement with such
underwriters prior to the time of sale, and the names of the underwriters used
in the transaction will be set forth in a prospectus supplement or a supplement
thereto relating to such sale. If an underwriting agreement is executed, the
securities will be acquired by the underwriters for their own account and may be
resold from time to time in one or more transactions, including negotiated
transactions, at a fixed public offering price or at varying prices determined
at the time of the sale. Unless we otherwise indicate in the prospectus
supplement, the underwriting or purchase agreement will provide that the
underwriter or underwriters are obligated to purchase all of the securities
offered in the prospectus supplement if any are purchased.

    If any securities are sold through agents designated by us from time to
time, the prospectus supplement or a supplement thereto will name any such
agent, set forth any commissions payable by us to any such agent and the
obligations of such agent with respect to the securities. Unless otherwise
indicated in the prospectus supplement or a supplement thereto, any such agent
will be acting on a best efforts basis for the period of its appointment.

    Certain persons participating in an offering of the securities may engage in
transactions that stabilize, maintain or otherwise affect the price of the
securities. Specifically, the underwriters may sell more securities than they
are obligated to purchase in connection with the offering, creating a short
position for their own accounts. A short sale is covered if the short position
is no greater than the number or amount of securities available for purchase by
the underwriters under any overallotment option. The underwriters can close out
a covered short sale by exercising the overallotment option or purchasing these
securities in the open market. In determining the source of securities to close
out a covered short sale, the underwriters will consider, among other things,
the open market price of these securities compared to the price available under
the overallotment option. The underwriters may also sell these securities or any
other securities in excess of the overallotment option, creating a naked short
position. The underwriters must close out any naked short position by purchasing
securities in the open market. A naked short position is more likely to be
created if the underwriters are concerned that there may be downward pressure on
the price of these securities in the open market after pricing that could
adversely affect investors who purchase in the offering. As an additional means
of facilitating the offering, the underwriters may bid for, and purchase, these
securities in the open market to stabilize the price of these securities.
Finally, in any offering of the securities through a syndicate of underwriters,
the underwriting syndicate may also reclaim selling concessions allowed to an
underwriter or a dealer for distributing these securities in the offering, if
the syndicate repurchases previously

                                       18
<Page>
distributed securities to cover syndicate short positions or to stabilize the
price of these securities. Any of these activities may raise or maintain the
market price of these securities above independent market levels or prevent or
retard a decline in the market price of these securities. The underwriters are
not required to engage in these activities and may end any of these activities
at any time.

    No series of securities, when first issued, will have an established trading
market. Any underwriters or agents to or through whom securities are sold by us
for public offering and sale may make a market in such securities, but
underwriters and agents will not be obligated to do so and may discontinue any
market making at any time without notice. We cannot assure you as to the
liquidity of the trading market for any securities.

    In connection with the sale of the securities, any purchasers, underwriters
or agents may receive compensation from us or from purchasers in the form of
concessions or commissions. The underwriters will be, and any agents and any
dealers participating in the distribution of the securities may be, deemed to be
underwriters within the meaning of the Securities Act of 1933. The agreement
between us and any purchasers, underwriters or agents will contain reciprocal
covenants of indemnity, and will provide for contribution by us in respect of
our indemnity obligations, between us and the purchasers, underwriters, or
agents against certain liabilities, including liabilities under the Securities
Act of 1933.

    Underwriters, dealers and agents may engage in transactions with, or perform
services for, us and our affiliates in the ordinary course of business.

                                    EXPERTS

    The financial statements incorporated in this prospectus by reference to the
Annual Report on Form 10-K for the year ended December 31, 2002 have been so
incorporated in reliance on the report of PricewaterhouseCoopers LLP,
independent accountants, given on the authority of said firm as experts in
auditing and accounting.

                                 LEGAL MATTERS

    The validity of the securities and certain other matters will be passed upon
for us by Huber Lawrence & Abell, New York, New York, and for any underwriters,
dealers or agents by Shearman & Sterling, New York, New York. As of March 13,
2003, members of Huber Lawrence & Abell owned 6,315 shares of Energy East
Corporation, our parent company.

                                       19
<Page>
                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

    Expenses in connection with the issuance and distribution of the securities
being registered, other than underwriting compensation, are as follows:

<Table>
                                                           
SEC registration fee........................................  $   24,270
Accounting services.........................................  $  150,000
Printing expenses...........................................  $  150,000
Trustee fees and expenses...................................  $   75,000
Transfer agent and registrar fees...........................  $   25,000
Rating agency fees..........................................  $  300,000
Legal fees and expenses.....................................  $  225,000
Miscellaneous...............................................  $   90,000
                                                              ----------
      Total.................................................  $1,039,270
                                                              ==========
</Table>

    All of the above, except the SEC registration fee, are estimated.

ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS

    The Business Corporation Law of the State of New York provides that if a
derivative action is brought against a director or officer, the registrant may
indemnify him against amounts paid in settlement and reasonable expenses,
including attorneys' fees, incurred by him in connection with the defense or
settlement of such action, if such director or officer acted in good faith for a
purpose which he reasonably believed to be in the registrant's best interests,
except that no indemnification shall be made without court approval in respect
of a threatened action, or a pending action settled or otherwise disposed of, or
in respect of any matter as to which such director or officer has been found
liable to the registrant. In a nonderivative action or threatened action, the
Business Corporation Law provides that the registrant may indemnify a director
or officer against judgments, fines, amounts paid in settlement and reasonable
expenses, including attorneys' fees incurred by him in defending such action if
such director or officer acted in good faith for a purpose which he reasonably
believed to be in the best interests of the registrant and, in criminal actions
or proceedings, in addition, had no reasonable cause to believe that his conduct
was unlawful.

    Under the Business Corporation Law, a director or officer who is successful,
either in a derivative or nonderivative action, is entitled to indemnification
as outlined above. Under any other circumstances, such director or officer may
be indemnified only if certain conditions specified in the Business Corporation
Law are met. The indemnification provisions of the Business Corporation Law are
not exclusive of any other rights to which a director or officer seeking
indemnification may be entitled pursuant to the provisions of the certificate of
incorporation or the by-laws of a corporation or, whether authorized by such
certificate of incorporation or by-laws, pursuant to a shareholders' resolution,
a directors' resolution or an agreement providing for such indemnification.

    The above is a general summary of certain provisions of the Business
Corporation Law and is subject, in all cases, to the specific and detailed
provisions of Sections 721-725 of the Business Corporation Law.

    The registrant's By-Laws provide that to the extent not prohibited by law,
the registrant shall indemnify each person made, or threatened to be made, a
party to any civil or criminal action or

                                      II-1
<Page>
proceeding by reason of the fact that he, or his testator or intestate, (i) is
or was a director, officer or employee of the registrant or (ii) is or was
serving any other corporation of any type or kind, domestic or foreign, or any
partnership, joint venture, trust, employee benefit plan or other enterprise, in
any capacity at the registrant's request.

    The registrant's By-Laws also provide, among other things, that:

    (1) no indemnification shall be made to or on behalf of any director,
officer or employee, if a judgment or other final adjudication adverse to the
director, officer or employee establishes that his acts were committed in bad
faith or were the result of active and deliberate dishonesty and were material
to the cause of action so adjudicated, or that he personally gained in fact a
financial profit or other advantage to which he was not legally entitled;

    (2) the rights to indemnification and advancement of defense expenses
granted by or pursuant to the By-Laws shall not limit or exclude, but shall be
in addition to, any other rights which may be granted by or pursuant to any
statute, certificate of incorporation, by-law, resolution or agreement; and

    (3) the registrant may, with the approval of its Board of Directors, enter
into an agreement with any person who is, or is about to become, a director,
officer or employee of the registrant, or who is serving, or is about to serve,
at the request of the registrant, as a director, officer, or in any other
capacity, any other corporation of any type or kind, domestic or foreign, or any
partnership, joint venture, trust, employee benefit plan or other enterprise,
which agreement may provide for indemnification of such person and advancement
of defense expenses to such person upon such terms, and to the extent, not
prohibited by law.

    The registrant has insurance policies indemnifying its directors and
officers against certain obligations that may be incurred by them, subject to
certain retention and co-insurance provisions.

ITEM 16. EXHIBITS

    See Exhibit Index.

ITEM 17. UNDERTAKINGS

    The undersigned registrant hereby undertakes:

    (1) to file, during any period in which offers or sales are being made, a
post-effective amendment to this registration statement:

        (i) to include any prospectus required by Section 10(a)(3) of the
    Securities Act of 1933;

        (ii) to reflect in the prospectus any facts or events arising after the
    effective date of the registration statement (or the most recent
    post-effective amendment thereof) which, individually or in the aggregate,
    represent a fundamental change in the information set forth in the
    registration statement. Notwithstanding the foregoing, any increase or
    decrease in the volume of securities offered (if the total dollar value of
    securities offered would not exceed that which was registered) and any
    deviation from the low or high end of the estimated maximum offering range
    may be reflected in the form of prospectus filed with the Commission
    pursuant to Rule 424(b) if, in the aggregate, the changes in volume and
    price represent no more than a 20% change in the maximum aggregate offering
    price set forth in the "Calculation of Registration Fee" table in the
    effective registration statement; and

        (iii) to include any material information with respect to the plan of
    distribution not previously disclosed in the registration statement or any
    material change to such information in the registration statement;

                                      II-2
<Page>
PROVIDED, HOWEVER, that paragraphs (i) and (ii) do not apply if the registration
statement is on Form S-3, Form S-8 or Form F-3, and the information required to
be included in a post-effective amendment by those paragraphs is contained in
periodic reports filed with or furnished to the Commission by the undersigned
registrant pursuant to Section 13 or 15(d) of the Securities Exchange Act of
1934 that are incorporated by reference in the registration statement;

    (2) that, for the purpose of determining any liability under the Securities
Act of 1933, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial BONA
FIDE offering thereof; and

    (3) to remove from registration by means of a post-effective amendment any
of the securities being registered which remain unsold at the termination of the
offering.

    The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of such
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial BONA FIDE offering thereof.

    Insofar as indemnification for liabilities arising under the Securities Act
of 1933 may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions, or otherwise, the registrant
has been advised that in the opinion of the Commission such indemnification is
against public policy as expressed in the Securities Act of 1933 and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by a registrant of expenses incurred or
paid by a director, officer or controlling person of such registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act of 1933 and will be governed by the
final adjudication of such issue.

                                      II-3
<Page>
                                   SIGNATURES

    Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of New York, State of New York, on March 19, 2003.

<Table>
                                            
                                               NEW YORK STATE ELECTRIC & GAS CORPORATION

                                               By: /s/ FRANK LEE
                                               Frank Lee
                                               ATTORNEY-IN-FACT
</Table>

    Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities indicated on March 19, 2003.

<Table>
<Caption>
                  SIGNATURE                                        TITLE
                  ---------                                        -----
                                            
Principal Executive Officer:

                      *                                   President and Director
- --------------------------------------------
              Ralph R. Tedesco

Principal Financial and Accounting Officer:

                      *                                  Senior Vice President and
- --------------------------------------------              Chief Financial Officer
            Sherwood J. Rafferty

Directors:

                      *                                          Director
- --------------------------------------------
            Wesley W. von Schack

                      *                                          Director
- --------------------------------------------
             Kenneth M. Jasinski

                /s/ FRANK LEE                    As attorney-in-fact for the officers and
- --------------------------------------------          directors marked by an asterisk
                  Frank Lee
</Table>

                                      II-4
<Page>
                                 EXHIBIT INDEX

<Table>
<Caption>
EXHIBIT NO.                                DESCRIPTION                              METHOD OF FILING
- -----------                                -----------                              ----------------
                                                                     
  1-1                   Form of Underwriting Agreement relating to the     Filed herewith.
                        senior unsecured debt securities.

  1-2                   Form of Underwriting Agreement relating to the     Filed herewith.
                        new preferred stock.

  4-1                   Unsecured Debt Indenture from New York State       Filed as Exhibit 4-7 to the
                        Electric & Gas Corporation to JPMorgan Chase       Company's 10-K for the year ended
                        Bank, as unsecured debt indenture trustee,         December 31, 2002 and incorporated
                        related to the senior unsecured debt securities.   herein by reference--File
                                                                           No. 1-3103-2.

  4-2                   Form of Senior Unsecured Debt Security             Included in Exhibit 4-1.

  4-3                   Restated Certificate of Incorporation of New York  Filed as Exhibit 4-11 to
                        State Electric & Gas Corporation pursuant to       Form S-3, Registration
                        section 807 of the Business Corporation Law filed  No. 33-50719 and incorporated
                        in the Office of the Secretary of State of the     herein by reference.
                        State of New York on October 25, 1988.

  4-4                   Certificate of Amendment of the Restated           Filed as Exhibit 4-12 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on October 17, 1989.                          herein by reference.

  4-5                   Certificate of Amendment of the Restated           Filed as Exhibit 4-13 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on May 22, 1990.                              herein by reference.

  4-6                   Certificate of Amendment of the Restated           Filed as Exhibit 4-14 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on October 31, 1990.                          herein by reference.

  4-7                   Certificate of Amendment of the Restated           Filed as Exhibit 4-15 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on February 6, 1991.                          herein by reference.

  4-8                   Certificate of Amendment of the Restated           Filed as Exhibit 4-16 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on October 15, 1991.                          herein by reference.

  4-9                   Certificate of Amendment of the Restated           Filed as Exhibit 4-17 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on May 28, 1992.                              herein by reference.

  4-10                  Certificate of Amendment of the Restated           Filed as Exhibit 4-18 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on October 20, 1992.                          herein by reference.

  4-11                  Certificate of Amendment of the Restated           Filed as Exhibit 4-19 to
                        Certificate of Incorporation filed in the Office   Form S-3, Registration
                        of the Secretary of State of the State of New      No. 33-50719 and incorporated
                        York on October 14, 1993.                          herein by reference.

  4-12                  Certificate of Amendment of the Restated           Filed as Exhibit 3-11 to the
                        Certificate of Incorporation filed in the Office   Company's 10-K for the year ended
                        of the Secretary of State of the State of New      December 31, 1993 and incorporated
                        York on December 10, 1993.                         herein by reference--File No.
                                                                           1-3103-2.
</Table>

<Page>

<Table>
<Caption>
EXHIBIT NO.                                DESCRIPTION                              METHOD OF FILING
- -----------                                -----------                              ----------------
                                                                     
  4-13                  Certificate of Amendment of the Restated           Filed as Exhibit 3-12 to the
                        Certificate of Incorporation filed in the Office   Company's 10-K for the year ended
                        of the Secretary of State of the State of New      December 31, 1993 and incorporated
                        York on December 20, 1993.                         herein by reference--File No.
                                                                           1-3103-2.

  4-14                  Certificate of Amendment of the Restated           Filed as Exhibit 3-16 to the
                        Certificate of Incorporation filed in the Office   Company's 10-Q for the quarter
                        of the Secretary of State of the State of New      ended September 30, 2000 and
                        York on September 6, 2000.                         incorporated herein by
                                                                           reference--File No. 1-3103-2.

  4-15                  Certificate of Merger of Columbia Gas of New       Filed as Exhibit 4-20 to
                        York, Inc. into New York State Electric & Gas      Form S-3, Registration
                        Corporation filed in the Office of the Secretary   No. 33-50719 and incorporated
                        of State of the State of New York on April 8,      herein by reference.
                        1991.

  4-16                  Form of 805 Certificate relating to the            Filed as Exhibit 4-21 to
                        designations, etc. of the new preferred stock.     Form S-3, Registration
                                                                           No. 33-50719 and incorporated
                                                                           herein by reference.

  4-17                  Certificates of the Secretary of New York State    Filed as Exhibit 3-16 to the
                        Electric & Gas Corporation concerning consents     Company's 10-Q for the quarter
                        dated March 20, 1957, May 9, 1975 and April 1,     ended March 31, 1999 and
                        1999 of holders of serial preferred stock with     incorporated herein by
                        respect to issuance of certain unsecured           reference--File No. 1-3103-2.
                        indebtedness.

  4-18                  By-Laws of New York State Electric & Gas           Filed as Exhibit 3-17 to the
                        Corporation as amended on June 28, 2002.           Company's 10-Q for the quarter
                                                                           ended June 30, 2002 and
                                                                           incorporated herein by
                                                                           reference--File No. 1-3103-2.

  5                     Opinion of Huber Lawrence & Abell with respect to  Filed herewith.
                        the legality of the senior unsecured debt
                        securities and the new preferred stock registered
                        hereunder.

  12-1                  Computation of ratio of earnings to fixed          Filed herewith.
                        charges.

  12-2                  Computation of ratio of earnings to fixed charges  Filed herewith.
                        and preferred stock dividends.

  23-1                  Consent of PricewaterhouseCoopers LLP.             Filed herewith.

  23-2                  Consent of Huber Lawrence & Abell.                 Included in opinion filed as
                                                                           Exhibit No. 5.

  24-1                  Power of Attorney of directors and officers.       Filed herewith.

  24-2                  Power of Attorney of New York State Electric &     Filed herewith.
                        Gas Corporation.

  25                    Statement of Eligibility of JPMorgan Chase Bank    Filed herewith.
                        as unsecured debt indenture trustee under the
                        unsecured debt indenture.
</Table>