KEYSPAN CORPORATION

                              4.650% NOTE DUE 2013

                                                               PRINCIPAL AMOUNT
REGISTERED                                                     $150,000,000

                                                               CUSIP No.
                                                               49337W AG 5
No. R-1
                                                               ISIN No.
                                                               US49337WAG50


THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER
REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A NOMINEE THEREOF.
UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES IN CERTIFICATED
FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITORY TRUST
COMPANY (THE "DEPOSITARY") TO A NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY
OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR
DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITARY TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND ANY NOTE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH
OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY
(AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY), ANY TRANSFER, PLEDGE OR
OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH
AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

          KEYSPAN CORPORATION, a New York corporation (the "Issuer" or the
"Company," which terms include any successor corporation under the Indenture
hereinafter referred to), for value received, hereby promises to pay to CEDE &
CO., or registered assigns, the principal sum of ONE HUNDRED FIFTY MILLION
DOLLARS on April 1, 2013, and to pay interest thereon (computed on the basis
of a 360-day year of twelve 30-day months), semiannually on April 1 and
October 1 (the "Interest Payment Dates") of each year, commencing on October
1, 2003, at the rate per annum specified in the title of this Note from April
4, 2003 or the most recent Interest Payment Date to which interest had been
paid or duly provided for.

          The interest so payable and punctually paid or duly provided for on
any Interest Payment Date will as provided in the Indenture be paid to the
Person in whose name this Note (or one or more Predecessor Securities) is
registered at the close of business on the March 15 or September 15 preceding
such Interest Payment Date (the "Record Date"). Payment of the principal of
(and premium, if any) and interest on this Note will be made at the office or
agency of the Company maintained by the Company for such purpose in the
Borough of Manhattan, The

<PAGE>

City of New York, in such coin or currency of the United States of America as
at the time of payment is legal tender for payment of public and private
debts.

          Reference is hereby made to the further provisions of this Note set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

          Unless the certificate of authentication hereon has been executed by
or on behalf of JPMorgan Chase Bank, the Trustee for this Note under the
Indenture, or its successor thereunder, by the manual signature of one of its
authorized officers, this Note shall not be entitled to any benefit under the
Indenture or be valid or obligatory for any purpose.


                                      2

<PAGE>


          IN WITNESS WHEREOF, the Company has caused this instrument to be
duly executed, manually or in facsimile, and an imprint or facsimile of its
corporate seal to be imprinted hereon.



Dated: April 4, 2003



                                        KEYSPAN CORPORATION


                                        By:
                                           ------------------------------------
                                           Name:   Gerald Luterman
                                           Title:  Executive Vice President and
                                                   Chief Financial Officer



[SEAL]


                                        Attest:


                                        By:
                                           ------------------------------------
                                           Name:   Michael J. Taunton
                                           Title:  Vice President and Treasurer


CERTIFICATE OF AUTHENTICATION

This is one of the Securities of the series designated therein described in the
within-mentioned Indenture.

JPMORGAN CHASE BANK,
  as Trustee

By:
   -----------------------------------
   Authorized Officer


                                      3

<PAGE>

                               (Reverse of Note)

                              KEYSPAN CORPORATION

          This Note is one of a duly authorized issue of Securities of the
Company designated as its 4.650% Notes due 2013 (the "Notes"). The Notes are
one of an indefinite number of series of debt securities of the Company (the
"Securities"), issued or issuable under and pursuant to an indenture (the
"Indenture") dated as of November 1, 2000, between the Company and JPMorgan
Chase Bank (formerly The Chase Manhattan Bank) (herein called the "Trustee,"
which term includes any successor Trustee under the Indenture), to which
Indenture and all indentures supplemental thereto reference is hereby made for
a statement of the respective rights thereunder of the Company, the Trustee
and the Holders of the Notes and the terms upon which the Notes are to be
authenticated and delivered. This Note is one of a series designated on the
face hereof as initially limited (except as provided in the Indenture) in
aggregate principal amount to $150,000,000. The Company may from time to time
without notice to, or the consent of, the Holders of the Notes, create and
issue further Notes of the same series as the Notes offered hereby ranking
pari passu with the Notes in all respects (or in all respects except for the
payment of interest accruing prior to the issue date of the new securities or
except for the first payment of interest following the issue date of the new
securities) so that the new securities may be consolidated and form a single
series with the Notes and have the same terms as the Notes. The terms of other
series of Securities issued under the Indenture may vary with respect to
interest rates or interest rate formulas, issue dates, maturity, redemption,
repayment, currency of payment and otherwise as provided in the Indenture. The
Indenture further provides that Securities of a single series may be issued at
various times, with different maturity dates and may bear interest at
different rates.

          This Note is not subject to any sinking fund.

          If an Event of Default (other than an Event of Default described in
Section 501(5) or 501(6) of the Indenture) with respect to the Notes shall
occur and be continuing, then either the Trustee or the Holders of not less
than 25% in aggregate principal amount of the Notes of this series then
Outstanding may declare the aggregate principal amount of the Notes of this
series due and payable in the manner and with the effect provided in the
Indenture. If an Event of Default specified in Section 501(5) or 501(6) occurs
with respect to the Company, all of the unpaid principal amount and accrued
interest thereon shall ipso facto become and be immediately due and payable in
the manner and with the effect provided in the Indenture without any
declaration or other act by the Trustee or any Holder.

          This Note may be redeemed in whole at any time or in part from time
to time at the option of the Company (such date of redemption, the "Optional
Redemption Date") at the Optional Redemption Price (as defined below) together
with interest accrued thereon to the Optional Redemption Date, on notice given
not more than 60 nor less than 30 days prior to the Optional Redemption Date.

          The "Optional Redemption Price" shall equal the sum of the principal
amount of the Note and the Make Whole Amount (as defined below). "Make-Whole
Amount" means, the excess, if any, of the aggregate present value as of the
Optional Redemption Date of principal

                                      4

<PAGE>

being redeemed and the amount of interest (exclusive of interest accrued to
the Optional Redemption Date) that would have been payable if redemption had
not been made, determined by discounting, on a semiannual basis, the remaining
principal and interest at the Reinvestment Rate (as defined below) (determined
on the third Business Day preceding the date notice of redemption is given)
from the dates on which the principal and interest would have been payable if
the redemption had not been made, to the Optional Redemption Date, over the
aggregate principal amount being redeemed.

          "Reinvestment Rate" shall mean 15 basis points plus the arithmetic
mean of the yield under the heading "Week Ending" published in the most recent
Statistical Release under the caption "Treasury Constant Maturities" for the
maturity (rounded to the nearest month) corresponding to the remaining life to
maturity, as of the payment date of the principal being redeemed. If no
maturity exactly corresponds to the remaining life to maturity of the
principal being redeemed, yields for the two published maturities most closely
corresponding to the maturity shall be so calculated and the Reinvestment Rate
shall be interpolated or extrapolated on a straight-line basis, rounding to
the nearest month. The most recent Statistical Release published prior to the
date of determination of the Make-Whole Amount shall be used for purposes of
calculating the Reinvestment Rate.

          "Statistical Release" shall mean the statistical release designated
"H.15(519)" or any successor publication which is published weekly by the
Federal Reserve System and which establishes yields on actively-traded United
States government securities adjusted to constant maturities, or, if such
statistical release is not published at the time of any determination under
the terms of the Notes, then such other reasonably comparable index which will
be designated by the Company.

          The Make-Whole Amount shall be calculated by an independent
investment banking institution of national standing appointed by the Company.
If the Reinvestment Rate is not available as described above, the Reinvestment
Rate shall be calculated by interpolation or extrapolation of comparable rates
selected by the independent investment banking institution.

          The Indenture permits, with certain exceptions as therein provided,
the Company and the Trustee with the consent of the Holders of more than 50%
in principal amount of the Securities at the time Outstanding of each series
issued under the Indenture to be affected thereby, to execute supplemental
indentures for the purpose of adding any provisions to or changing in any
manner or eliminating any of the provisions of the Indenture or of modifying
in any manner the rights of the Holders of the Securities of such series;
provided, however, that no such supplemental indenture shall, among other
things, (i) change the Stated Maturity of the principal of, or any installment
of principal of or interest on, any Security, or reduce the principal amount
thereof or interest thereon, if any, or any premium payable upon redemption
thereof, or (ii) change the Place of Payment on any Security or the currency
or currency unit in which any Security or the principal or interest thereon is
payable; impair the right to institute suit for the enforcement of any such
payment on or after the Stated Maturity thereof; or reduce or alter the method
of computation of any amount payable upon redemption, repayment or purchase of
any Securities by the Company (or the time when such redemption, repayment or
purchase may be made); or reduce the percentage in principal amount of the
Securities, the Holders of which are required to consent to any supplemental
indenture, without the consent of the Holder of each

                                      5

<PAGE>

Security affected thereby. The Indenture also contains provisions permitting
the Holders of more than 50% in principal amount of the Securities of each
series at the time outstanding, on behalf of the Holders of all the Securities
of that series, to waive compliance by the Company with certain provisions of
the Indenture and certain past defaults under the Indenture and their
consequences with respect to such series, except a default in the payment of
principal of or interest, if any, on any Security of that series or a default
with respect to a covenant or provision of the Indenture which cannot be
amended without the consent of such Holder.

          The Notes are issuable only in registered form without coupons in
denominations of $1,000 and integral multiples thereof. As provided in the
Indenture and subject to certain limitations therein set forth, the Notes are
exchangeable for a like aggregate principal amount of Notes as requested by
the Holder surrendering the same. If (x) the Depositary is at any time
unwilling or unable to continue as depositary and a successor depositary is
not appointed by the Company within 90 days after the Company receives such
notice or becomes aware of such ineligibility, (y) the Company delivers to the
Trustee a Company Order to the effect that this Note shall be exchangeable or,
(z) an Event of Default has occurred and is continuing with respect to the
Notes, this Note shall be exchangeable for Notes in definitive form and in an
equal aggregate principal amount. Such definitive Notes shall be registered in
such name or names as the Depositary shall instruct the Trustee.

          As provided in the Indenture and subject to certain limitations set
forth therein and above, the transfer of this Note may be registered on the
Security Register of the Company, upon surrender of this Note for registration
of transfer at the office or agency of the Company in the Borough of
Manhattan, The City of New York, duly endorsed by, or accompanied by a written
instrument of transfer in form satisfactory to the Company and the Security
Registrar duly executed by, the Holder hereof or by his attorney duly
authorized in writing, and thereupon one or more new Notes of authorized
denominations and for the same aggregate principal amount will be issued to
the designated transferee or transferees.

          No reference herein to the Indenture and no provision of this Note
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of (and premium, if any)
and interest on this Note at the time, place and rate, and in the coin or
currency, herein and in the Indenture prescribed.

          No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient
to cover any tax or other governmental charge payable in connection therewith.

          Prior to due presentment of this Note for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name this Note is registered as the owner hereof for all
purposes, whether or not this Note be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

          Certain of the Company's obligations under the Indenture with
respect to Notes, may be terminated if the Company irrevocably deposits with
the Trustee money or Government

                                      6

<PAGE>

Obligations sufficient to pay and discharge the entire indebtedness on all
Notes, as provided in the Indenture.

          No recourse shall be had for the payment of the principal of (and
premium, if any), or the interest, if any, on this Note, or for any claim
based thereon, or upon any obligation, covenant or agreement of the Company in
the Indenture, against the any incorporator, stockholder, officer or director,
as such, past, present or future, of the Company or of any successor
corporation, whether by virtue of any constitution, statute or rule of law or
by the enforcement of any assessment of penalty or otherwise; and all such
personal liability is expressly released and waived as a condition of, and as
part of the consideration for, the issuance of this Note.

          The Indenture and the Notes shall be governed by and construed in
accordance with the laws of the State of New York.

          All terms used in this Note which are defined in the Indenture shall
have the meanings assigned to them in the Indenture.

                                      7

<PAGE>


                           ASSIGNMENT/TRANSFER FORM

          FOR VALUE RECEIVED the undersigned registered Holder hereby sell(s),
assign(s) and transfer(s) unto (insert Taxpayer Identification No.)
_____________________________________________________________________________
_____________________________________________________________________________
_____________________________________________________________________________
(Please print or typewrite name and address including postal zip code of
assignee)
_________________________________________________________________________ the
within Note and all rights thereunder, hereby irrevocably constituting and
appointing _______________________________________ attorney to transfer said
Note on the books of the Company with full power of substitution in the
premises.

                  Date:___________________

          ________________________________________ NOTICE: The signature of
the registered Holder to this assignment must correspond with the name as
written upon the face of the within instrument in every particular, without
alteration or enlargement or any change whatsoever.


                                      8