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                                                                    EXHIBIT 4.22

                                                                  EXECUTION COPY

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                                   ONEOK, INC.

                           4.0% Senior Notes due 2008

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

                          FIRST SUPPLEMENTAL INDENTURE

                          Dated as of January 28, 2003

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

                                  SunTrust Bank

                                     TRUSTEE


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     THIS FIRST SUPPLEMENTAL INDENTURE is made as of the 28th day of January,
2003, by and between ONEOK, INC., an Oklahoma corporation (the "Company"), and
SUNTRUST BANK, a Georgia banking corporation, as trustee (the "Trustee").

                              W I T N E S S E T H:

     WHEREAS, the Company has heretofore entered into an Indenture, dated as of
December 28, 2001 (the "Original Indenture"), with the Trustee;

     WHEREAS, the Original Indenture is incorporated herein by this reference
and the Original Indenture, as supplemented by this First Supplemental
Indenture, is herein called the "Indenture";

     WHEREAS, under the Original Indenture, a new series of Securities may at
any time be established pursuant to a supplemental indenture executed by the
Company and the Trustee;

     WHEREAS, the Company proposes to create under the Indenture a new series of
Securities; and

     WHEREAS, all conditions necessary to authorize the execution and delivery
of this First Supplemental Indenture and to make it a valid and binding
obligation of the Company have been done or performed.

     NOW, THEREFORE, in consideration of the agreements and obligations set
forth herein and for other good and valuable consideration, the sufficiency of
which is hereby acknowledged, the parties hereto hereby agree as follows:

                                    ARTICLE 1

                           4.0% SENIOR NOTES DUE 2008

     SECTION 101. Establishment. There is hereby established a new series of
Securities to be issued under the Indenture, to be designated as the Company's
4.0% Senior Notes due 2008 (the "Senior Notes").

     There are to be authenticated and delivered $350,000,000.00 (and up to an
additional $52,500,000.00 to the extent that the underwriters' over-allotment
option is exercised) principal amount of Senior Notes to be issued to
underwriters at 100% of principal amount. The Company shall have the right to
issue additional Senior Notes at any time upon compliance with the provisions of
the Indenture applicable to the issuance of additional Securities. Except as set
forth in Section 105, the Senior Notes shall be issued in definitive fully
registered, certificated form, bearing identical terms.

     The Senior Notes shall be issued initially in the form of one or more
Global Securities, each in substantially the form set out in Exhibit A hereto.
The initial Depositary with respect to the Senior Notes shall be The Depository
Trust Company.

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     The Company will not pay Additional Amounts, as defined in Section 1008 of
the Original Indenture.

     The form of the Trustee's Certificate of Authentication for the Senior
Notes shall be in substantially the form set forth in Exhibit B hereto.

     Each Senior Note shall be dated the date of authentication thereof and
shall bear interest from the Original Issue Date.

     Unless the Special Event Redemption occurs prior to the Maturity Date, the
date upon which the Senior Notes shall become due and payable at final maturity,
together with any accrued and unpaid interest is, the Maturity Date.

     The interest rate on the Senior Notes may be reset pursuant to Section
308(b) of the Original Indenture and the Maturity Date shall not be extended
pursuant to Section 309 of the Original Indenture.

     SECTION 102. Definitions. The following defined terms used herein shall,
unless the context otherwise requires, have the meanings specified below.
Capitalized terms used herein for which no definition is provided herein shall
have the meanings set forth in the Original Indenture.

     "Accounting Event" means the receipt by the audit committee of the board of
directors of the Company of a written report in accordance with Statement on
Auditing Standards ("SAS") No. 97, "Amendment to SAS No. 50 -Reports on the
Application of Accounting Principles", from the Company's independent auditors,
provided at the request of the management of the Company, to the effect that, as
a result of a change in accounting rules after the date hereof, the Company must
either (i) account for all or any portion of the Purchase Contracts as a
derivative under SFAS 133 (or otherwise mark-to-market or measure at fair value
all or any portion of the Purchase Contracts, with changes appearing in the
Company's income statement) or (ii) account for the Units using the if-converted
method under SFAS 128, and that such accounting treatment will cease to apply
upon redemption of the Senior Notes.

     "Applicable Principal Amount" means the aggregate principal amount of the
Senior Notes that are components of Corporate Units.

     "Beneficial Owner" shall have the meaning specified in the Purchase
Contract Agreement.

     "Business Day" shall have the meaning specified in the Purchase Contract
Agreement.

     "Corporate Units" shall have the meaning specified in the Purchase Contract
Agreement.

     "Coupon Rate" shall have the meaning set forth in Section 103(a).

     "Custodial Agent" shall have the meaning set forth in the Purchase Contract
Agreement.

                                      - 2 -

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     "Depositary" means a clearing agency registered under Section 17A of the
Securities Exchange Act of 1934, as amended, that is designated to act as
Depositary for the Corporate Units pursuant to the Purchase Contract Agreement.

     "Depositary Participant" means a broker, dealer, bank, other financial
institution or other Person for whom from time to time the Depositary effects
book entry transfers and pledges of securities deposited with the Depositary.

     "Failed Remarketing" shall have the meaning set forth in the Purchase
Contract Agreement.

     "Final Remarketing" shall have the meaning set forth in the Purchase
Contract Agreement.

     "Final Remarketing Price" shall have the meaning set forth in Section
302(b).

     "Global Securities" shall have the meaning set forth in Section 105.

     "Interest Payment Dates" shall have the meaning specified in Section
103(a).

     "Maturity Date" means February 16, 2008.

     "Original Issue Date" means January 28, 2003.

     "Pledge Agreement" means the Pledge Agreement, dated as of January 28, 2003
among the Company, SunTrust Bank, as Collateral Agent, Custodial Agent and
Securities Intermediary, and SunTrust Bank, as purchase contract agent,
attorney-in-fact and trustee for the Holders of the Purchase Contracts, as
amended from time to time.

     "Purchase Contract Agreement" means the Purchase Contract Agreement, dated
as of January 28, 2003, between the Company and SunTrust Bank, as purchase
contract agent, attorney-in-fact and trustee, as amended from time to time.

     "Purchase Contract Settlement Date" means February 16, 2006.

     "Purchase Contracts" and "Purchase Contract" shall have their respective
meanings specified in the Purchase Contract Agreement.

     "Put Price" shall have the meaning set forth in Section 305(a).

     "Put Right" shall have the meaning set forth in Section 305(a).

     "Quotation Agent" means any primary U.S. government securities dealer
selected by the Company.

     "Record Date" means, with respect to any Interest Payment Date for the
Senior Notes, the first Business Day of the calendar month in which such
Interest Payment Date falls; provided that the Company may, at its option,
select any other day as the Record Date for any Interest

                                      - 3 -

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Payment Date so long as such Record Date selected is more than one Business Day
but less than sixty Business Days prior to such Interest Payment Date.

     "Redemption Amount" shall mean, for each Senior Note, an amount equal to
the product of the principal amount of that Senior Note and a fraction, the
numerator of which is the Treasury Portfolio Purchase Price and the denominator
of which is the Applicable Principal Amount.

     "Redemption Price" shall mean, for each Senior Note, the Redemption Amount
plus any accrued and unpaid interest on such Senior Note to but excluding the
Special Event Redemption Date.

     "Remarketed Senior Notes" shall have the meaning set forth in Section
301(c).

     "Remarketing Agent" shall have the meaning set forth in the Remarketing
Agreement.

     "Remarketing Agreement" means the Remarketing Agreement, dated as of
January 28, 2003, among the Company, UBS Warburg LLC, Banc of America Securities
LLC and J.P. Morgan Securities Inc., each as a potential Remarketing Agent, and
SunTrust Bank, as purchase contract agent, attorney-in-fact and trustee, as
amended from time to time.

     "Remarketing Date" shall have the meaning set forth in the Purchase
Contract Agreement"

     "Remarketing Price" shall have the meaning set forth in Section 302(a).

     "Reset Effective Date" means the date three Business Days following the
date of a Successful Remarketing pursuant to which the Coupon Rate is reset to a
Reset Rate.

     "Reset Rate" means the interest rate per annum on the Senior Notes (i) in
the case of a Successful Remarketing prior to the Final Remarketing Date, as
determined by the Remarketing Agent as necessary to remarket the Remarketed
Senior Notes at a price per Remarketed Senior Note such that the aggregate price
for the Remarketed Senior Notes is equal to approximately 100.50% of the sum of
the Treasury Portfolio Purchase Price and Separate Senior Notes Purchase Price,
and (ii) in the case of a Successful Remarketing on the Final Remarketing Date,
as the rate necessary to remarket the Remarketed Senior Notes at a price per
Remarketed Senior Note such that the aggregate price for the Remarketed Senior
Notes is equal to approximately 100.50% of the aggregate principal amount of the
Remarketed Senior Notes; provided that if there are no Corporate Units
outstanding and none of the Holders elect to have Separate Senior Notes held by
them remarketed, or in the case of a Failed Remarketing, the interest rate
payable on the Senior Notes will not be reset and the interest rate payable on
the Senior Notes shall continue to be the Coupon Rate; provided further that in
no event shall the Reset Rate exceed the maximum rate, if any, permitted by
applicable law.

     "Separate Senior Notes" means Senior Notes that are no longer a component
of Corporate Units.

                                      - 4 -

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     "Separate Senior Notes Purchase Price" shall have the meaning set forth in
the Purchase Contract Agreement.

     "Special Event" shall mean either a Tax Event or an Accounting Event.

     "Special Event Redemption" means the redemption of the Senior Notes
pursuant to the terms hereof following the occurrence of a Special Event.

     "Special Event Redemption Date" shall have the meaning set forth in Section
201.

     "Successful Remarketing" shall have the meaning set forth in the Purchase
Contract Agreement.

     "Tax Event" means the receipt by the Company of an opinion of counsel,
rendered by a law firm having a recognized national law practice, to the effect
that, as a result of any amendment to, change in or announced proposed change in
the laws (or any regulations thereunder) of the United States or any political
subdivision or taxing authority thereof or therein, or as a result of any
official administrative decision, pronouncement, judicial decision or action
interpreting or applying such laws or regulations, which amendment or change is
effective or which proposed change, pronouncement, action or decision is
announced on or after the date hereof, there is more than an insubstantial
increase in the risk that interest payable by the Company on the Senior Notes is
not, or within 90 days of the date of such opinion, will not be, deductible by
the Company, in whole or in part, for United States federal income tax purposes.

     "Treasury Portfolio" means a portfolio of (1) U.S. treasury securities (or
principal or interest strips thereof) that mature on or prior to February 15,
2006 in an aggregate amount equal to the Applicable Principal Amount, and (2)
(x) in the case of a Successful Remarketing prior to the Final Remarketing Date,
for the scheduled Interest Payment Date on the Purchase Contract Settlement
Date, U.S. treasury securities (or principal or interest strips thereof) that
mature on or prior to February 15, 2006 in an aggregate amount equal to the
aggregate interest payment (assuming no reset of the interest rate) that would
have been due on the Purchase Contract Settlement Date on the Applicable
Principal Amount, and (y) in the case of a Special Event Redemption, for each
scheduled Interest Payment Date that occurs after the Special Event Redemption
Date to and including the Purchase Contract Settlement Date, U.S. treasury
securities (or principal or interest strips thereof) that mature on or prior to
the business day immediately preceding such scheduled Interest Payment Date in
an aggregate amount equal to the aggregate interest payment (assuming no reset
of the interest rate) that would have been due on such scheduled Interest
Payment Date on the Applicable Principal Amount.

     "Treasury Portfolio Purchase Price" means the lowest aggregate ask-side
price quoted by a Primary Treasury Dealer to the Quotation Agent between 9:00
a.m. and 11:00 a.m. (New York City time) (i) in the case of a Special Event
Redemption, on the third Business Day immediately preceding the Special Event
Redemption Date for the purchase of the applicable Treasury Portfolio for
settlement on the Special Event Redemption Date, and (ii) in the case of a
Successful Remarketing prior to the Final Remarketing Date, on the date of such
Successful Remarketing for the purchase of the applicable Treasury Portfolio for
settlement on the third Business Day immediately following the date of such
Successful Remarketing.

                                      - 5 -

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     "Treasury Units" shall have the meaning specified in the Purchase Contract
Agreement.

     "Units" shall have the meaning specified in the Purchase Contract
Agreement.

     SECTION 103. Payment of Principal and Interest.

          (a)  The Senior Notes will bear interest initially at the rate of 4.0%
per year (the "Coupon Rate") from the original date of issuance through and
including the earlier of (i) the Maturity Date and (ii) the day immediately
preceding any Reset Effective Date. In the event of a Successful Remarketing of
the Senior Notes, the Coupon Rate will be reset by the Remarketing Agent at the
appropriate Reset Rate with effect from the related Reset Effective Date, as set
forth under Section 303. If the Coupon Rate is so reset, the Senior Notes will
bear interest at the Reset Rate from the related Reset Effective Date until the
principal thereof and interest thereon is paid or duly made available for
payment and shall bear interest, to the extent permitted by law, compounded
quarterly, on any overdue principal and payment of interest at the Coupon Rate
through and including the day immediately preceding the Reset Effective Date and
at the Reset Rate thereafter.

          (b)  Interest on the Senior Notes shall be payable quarterly in
arrears on February 16, May 16, August 16 and November 16 of each year (each, an
"Interest Payment Date"), commencing May 16, 2003, to the Person in whose name
such Senior Note, or any predecessor Senior Note, is registered at the close of
business on the Record Date for such Interest Payment Date. Interest on the
Senior Notes shall accrue from January 28, 2003.

          (c)  The amount of interest payable for any full quarterly period will
be computed on the basis of a 360-day year consisting of twelve 30-day months.
The amount of interest payable for any period shorter than a full quarterly
period for which interest is computed will be computed on the basis of a 30-day
month and, for any period less than a month, on the basis of the actual number
of days elapsed per 30-day month. In the event that any scheduled Interest
Payment Date falls on a day that is not a Business Day, then payment of interest
payable on such Interest Payment Date will be made on the next succeeding day
which is a Business Day (and without any interest or other payment in respect of
any such delay), except that, if such Business Day is in the next calendar year,
then such payment will be made on the preceding Business Day.

          (d)  Principal of and interest on the Senior Notes will be payable,
the transfer of such Senior Notes will be registrable, and such Senior Notes
will be exchangeable for Senior Notes of a like aggregate principal amount
bearing identical terms and provisions, at the office or agency of the Company
maintained for such purpose in the Borough of Manhattan, City and State of New
York, or at the Corporate Trust Office of the Trustee. The principal of and
interest on the Notes shall be paid in such currency of the United States of
America as at the time of payment is legal tender for payment of public and
private debts. Payments of interest will be made at the option of the Company,
by (i) check mailed to the Holder at such address as shall appear in the
Security Register or (ii) wire transfer to an account appropriately designated
by the Holder entitled to payment.

                                      - 6 -

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     The Security Registrar and Paying Agent for the Senior Notes shall
initially be the Trustee.

     SECTION 104. Denominations. The Senior Notes may be issued in denominations
of $25.00 or any integral multiples of $25.00 in excess thereof.

     SECTION 105. Global Securities. Senior Notes that are no longer a component
of the Corporate Units and released from the Collateral Account (as defined in
the Pledge Agreement) will be issued in permanent global form (a "Global
Security"), and if issued as one or more Global Securities, the Depositary shall
be The Depository Trust Company or such other depositary as any officer of the
Company may from time to time designate. Upon the creation of Treasury Units or
the recreation of Corporate Units, an appropriate annotation shall be made on
the Schedule of Increases or Decreases on the Global Securities held by the
Depositary. Unless and until such Global Security is exchanged for Senior Notes
in certificated form, Global Securities may be transferred, in whole but not in
part, and any payments on the Senior Notes shall be made, only to the Depositary
or a nominee of the Depositary, or to a successor Depositary selected or
approved by the Company or to a nominee of such successor Depositary.

     Owners of beneficial interests in a Global Security will not be considered
the Holders thereof for any purpose under the Indenture, and no Global Security
representing a Senior Note shall be exchangeable, except for another Global
Security of like denomination and tenor to be registered in the name of the
Depositary or its nominee or to a successor Depositary or its nominee. The
rights of Holders of such Global Security shall be exercised only through the
Depositary.

     A Global Security shall be exchangeable for Senior Notes registered in the
names of persons other than the Depositary or its nominee only if (i) the
Depositary notifies the Company that it is unwilling or unable to continue as a
Depositary for such Global Security and no successor Depositary shall have been
appointed by the Company, or if at any time the Depositary ceases to be a
clearing agency registered under the Securities Exchange Act of 1934, as
amended, at a time when the Depositary is required to be so registered to act as
such Depositary and no successor Depositary shall have been appointed by the
Company, in each case within 90 days after the Company receives such notice or
becomes aware of such cessation, (ii) the Company in its sole discretion
determines that such Global Security shall be so exchangeable, or (iii) there
shall have occurred an Event of Default with respect to the Notes.

     SECTION 106. Transfer. No service charge will be made for any transfer or
exchange of Senior Notes, but the Company may require payment from the Holder of
a sum sufficient to cover any tax or other governmental charge that may be
imposed in connection therewith.

     SECTION 107. No Defeasance. The provisions of Section in 1502 of the
Original Indenture shall not apply to the Senior Notes

     SECTION 108. No Sinking Fund. The Senior Notes will not be entitled to the
benefit of any sinking fund.

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                                    ARTICLE 2

                         REDEMPTION OF THE SENIOR NOTES

     SECTION 201. Special Event Redemption. If a Special Event shall occur and
be continuing, the Company may, at its option, redeem the Senior Notes in whole,
but not in part, on any Interest Payment Date prior to the earlier of the date
of a Successful Remarketing or the Purchase Contract Settlement Date, at a price
per Senior Note equal to the Redemption Price, payable on the date of redemption
(the "Special Event Redemption Date") to the Holders of the Senior Notes
registered at the close of business on the Record Date for such Interest Payment
Date. If the Company so elects to redeem the Senior Notes, the Company shall
appoint the Quotation Agent to assist the Company in determining the Treasury
Portfolio Purchase Price. Notice of any Special Event Redemption will be mailed
by the Company (with a copy to the Trustee) at least 30 days but not more than
60 days before the Special Event Redemption Date to each registered Holder of
the Senior Notes at its registered address. In addition, the Company shall
notify the Collateral Agent in writing that a Special Event has occurred and
that the Company intends to redeem the Senior Notes on the Special Event
Redemption Date. Unless the Company defaults in the payment of the Redemption
Price, on and after the Special Event Redemption Date, (a) interest shall cease
to accrue on the Senior Notes, (b) the Senior Notes shall become due and payable
at the Redemption Price, and (c) the Senior Notes shall be void and all rights
of the Holders in respect of the Senior Notes shall terminate and lapse (other
than the right to receive the Redemption Price upon surrender of such Senior
Notes but without interest on such Redemption Price). Following the notice of a
Special Event Redemption, neither the Company nor the Trustee shall be required
to register the transfer of or exchange the Senior Notes to be redeemed.

     SECTION 202. Redemption Procedures. On or prior to the Special Event
Redemption Date, the Company shall deposit with the Trustee immediately
available funds in an amount sufficient to pay, on the Special Event Redemption
Date, the aggregate Redemption Price for all outstanding Senior Notes. In
exchange for any Senior Notes surrendered for redemption on or after the Special
Event Redemption Date, the Trustee shall pay an amount equal to the Redemption
Price (a) to the Collateral Agent, in the case of Senior Notes that are included
in Corporate Units, which amount shall be applied by the Collateral Agent in
accordance with the terms of the Pledge Agreement, and (b) to the holders of the
Separate Senior Notes, in the case of Separate Senior Notes.

                                    ARTICLE 3

                                   REMARKETING

     SECTION 301. Remarketing Procedures.

          (a)  Unless a Special Event Redemption or a Successful Remarketing has
occurred prior to the applicable Remarketing Date, the Company shall engage the
Remarketing Agent pursuant to the Remarketing Agreement for the remarketing of
the Senior Notes. The Company will request, not later than seven nor more than
15 calendar days prior to the applicable Remarketing Date, that the Depositary
or its nominee notify the Beneficial Owners or

                                      - 8 -

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Depositary Participants holding Separate Senior Notes, Corporate Units and
Treasury Units of the procedures to be followed in the applicable remarketing.

          (b)  Each Holder of Separate Senior Notes may elect to have Separate
Senior Notes held by such Holder remarketed in any remarketing. A Holder making
such an election must, pursuant to the Pledge Agreement, notify the Custodial
Agent and deliver such Separate Senior Notes to the Custodial Agent prior to
5:00 P.M. (New York City time) on or prior to the fifth Business Day immediately
preceding the applicable Remarketing Date (but no earlier than the Interest
Payment Date immediately preceding the applicable Remarketing Date). Any such
notice and delivery may not be conditioned upon the level at which the Reset
Rate is established in the Remarketing. Any such notice and delivery may be
withdrawn prior to 5:00 P.M. (New York City time) on or prior to the fifth
Business Day immediately preceding the applicable Remarketing Date in accordance
with the provisions set forth in the Pledge Agreement. Any such notice and
delivery not withdrawn by such time will be irrevocable with respect to such
remarketing. Pursuant to Section 4.07(c) of the Pledge Agreement, by 11:00 A.M.,
New York City time, on the Business Day immediately preceding the applicable
Remarketing Date, the Custodial Agent, based on the notices and deliveries
received by it prior to such time, shall notify the Remarketing Agent of the
principal amount of Separate Senior Notes to be tendered for remarketing and
shall cause such Separate Senior Notes to be presented to the Remarketing Agent.
Under Section 5.02 of the Purchase Contract Agreement, Senior Notes that are
components of Corporate Units will be deemed tendered for remarketing and will
be remarketed in accordance with the terms of the Remarketing Agreement.

          (c)  The right of each Holder of Senior Notes that are included in
Corporate Units to have such Senior Notes, and each Holder of Separate Senior
Notes to have any Separate Senior Notes (together, the "Remarketed Senior
Notes"), remarketed and sold on any Remarketing Date shall be limited to the
extent that (i) the Remarketing Agent conducts a remarketing pursuant to the
terms of the Remarketing Agreement, (ii) a Special Event Redemption has not
occurred prior to such Remarketing Date, (iii) the Remarketing Agent is able to
find a purchaser or purchasers for Remarketed Senior Notes at the Remarketing
Price or the Final Remarketing Price, as the case may be, and (iv) the purchaser
or purchasers deliver the purchase price therefor to the Remarketing Agent as
and when required.

          (d)  Neither the Trustee, the Company nor the Remarketing Agent shall
be obligated in any case to provide funds to make payment upon tender of Senior
Notes for remarketing.

     SECTION 302. Remarketing.

          (a)  Unless a Special Event Redemption has occurred prior to the
Initial Remarketing Date, on the Initial Remarketing Date, the Remarketing Agent
shall, pursuant and subject to the terms of the Remarketing Agreement, use its
reasonable efforts to remarket the Remarketed Senior Notes at a price (the
"Remarketing Price") equal to approximately 100.50% of the sum of the Treasury
Portfolio Purchase Price and the Separate Senior Note Purchase Price.

          (b)  In the case of a Failed Initial Remarketing and unless a Special
Event Redemption has occurred prior to the Final Remarketing Date, on the Final
Remarketing Date,

                                      - 9 -

<PAGE>

the Remarketing Agent shall use its reasonable efforts to remarket the
Remarketed Senior Notes at a price (the "Final Remarketing Price") equal to
approximately 100.50% of the aggregate principal amount of the Remarketed Senior
Notes. It is understood and agreed that remarketing on any Remarketing Date will
be considered successful and no further attempts will be made if the resulting
proceeds are at least 100.50% of the sum of the Treasury Portfolio Purchase
Price and the Separate Senior Note Purchase Price, in the case of the Initial
Remarketing, or 100.50% of the aggregate principal amount of the Remarketed
Senior Notes in the case of the Final Remarketing.

     SECTION 303. Reset Rate.

          (a)  In connection with each Remarketing, the Remarketing Agent shall
determine the Reset Rate (rounded to the nearest one-thousandth (0.001) of one
percent per annum) that the Remarketed Senior Notes should bear in order to have
an aggregate market value equal to the Remarketing Price or the Final
Remarketing Price, as the case may be, and that in the sole discretion of the
Remarketing Agent will enable it to remarket all of the Remarketed Senior Notes
at the Remarketing Price or Final Remarketing Price, as the case may be, in such
Remarketing.

          (b)  Anything herein to the contrary notwithstanding, the Reset Rate
shall in no event exceed the maximum rate permitted by applicable law and the
Remarketing Agent shall have no obligation to determine whether there is any
limitation under applicable law on the Reset Rate or, if there is any such
limitation, the maximum permissible Reset Rate on the Senior Notes and they
shall rely solely upon written notice from the Company (which the Company agrees
to provide prior to the eighth Business Day before the Initial Remarketing Date)
as to whether or not there is any such limitation and, if so, the maximum
permissible Reset Rate.

          (c)  In the event of a Failed Remarketing or if no Senior Notes are
included in Corporate Units and none of the holders of the Separate Senior Notes
elect to have their Senior Notes remarketed in any remarketing, the applicable
interest rate on the Senior Notes will not be reset and will continue to be the
Coupon Rate.

          (d)  In the event of a Successful Remarketing, the Coupon Rate shall
be reset at the Reset Rate as determined by the Remarketing Agent under the
Remarketing Agreement.

     SECTION 304. Failed Remarketing.

          (a)  If, by 4:00 p.m. (New York City time) on any Remarketing Date,
the Remarketing Agent is unable to remarket all of the Remarketed Senior Notes
at the Remarketing Price or the Final Remarketing Price, as the case may be,
pursuant to the terms and conditions hereof, a Failed Remarketing shall be
deemed to have occurred, and the Remarketing Agent shall so advise, by telephone
the Depositary, the Purchase Contract Agent and the Company. Promptly following
any Failed Remarketing, the Remarketing Agent shall return Separate Senior Notes
submitted for remarketing, if any, to the Custodial Agent for distribution to
the appropriate Holders.

                                     - 10 -

<PAGE>

          (b)  The Company shall cause a notice of such Failed Remarketing to be
published in a daily newspaper in the English language of general circulation in
the City of New York, which is expected to be The Wall Street Journal.

     SECTION 305. Put Right.

          (a)  If there has not been a Successful Remarketing prior to the
Purchase Contract Settlement Date, Holders of Separate Senior Notes and Holders
of Senior Notes that are a component of Corporate Units will, subject to this
Section 305, have the right (the "Put Right") to require the Company to purchase
their Senior Notes, on the Purchase Contract Settlement Date, at a price per
Senior Note equal to $25.00 plus accrued and unpaid interest to but excluding
the Purchase Contract Settlement Date (the "Put Price").

          (b)  The Put Right of Holders of Senior Notes that are part of
Corporate Units will be automatically exercised unless such Holders (1) prior to
11:00 a.m., New York City time, on the second Business Day immediately preceding
the Purchase Contract Settlement Date, provide written notice to the Purchase
Contract Agent of their intention to settle the related Purchase Contract with
separate cash, and (2) on or prior to the Business Day immediately preceding the
Purchase Contract Settlement Date, deliver to the Collateral Agent $25.00 in
cash per Purchase Contract, in each case pursuant to the Purchase Contract
Agreement. Unless a Corporate Unit holder has settled the related Purchase
Contract with separate cash on or prior to the Purchase Contract Settlement
Date, the Company, on the Purchase Contract Settlement Date, shall cause the Put
Price to be deposited in the Collateral Account and the Collateral Agent shall
cause the Securities Intermediary to remit the Purchase Price for the shares of
Common Stock to be issued under the related Purchase Contract from a portion of
the proceeds of the Put Right to the Company in full satisfaction of such
Holder's obligations under the related Purchase Contract. Any remaining amount
of the Put Price following satisfaction of the related Purchase Contract will be
paid to such Corporate Unit holder. If the Company shall fail to pay the Put
Price on the Purchase Contract Settlement Date in accordance with the foregoing,
the Company shall be deemed to have netted its obligation to pay the Put Price
against the obligation of a Holder of a Senior Note that is a component of a
Corporate Unit to pay the Purchase Price under the related Purchase Contract on
the Purchase Contract Settlement Date.

          (c)  The Put Right of a Holder of a Separate Senior Note shall only be
exercisable upon delivery of a notice to the Trustee by such Holder on or prior
to the second Business Day prior to the Purchase Contract Settlement Date. On or
prior to the Purchase Contract Settlement Date, the Company shall deposit with
the Trustee immediately available funds in an amount sufficient to pay, on the
Purchase Contract Settlement Date, the aggregate Put Price of all Separate
Senior Notes with respect to which a Holder has exercised a Put Right. In
exchange for any Separate Senior Notes surrendered pursuant to the Put Right,
the Trustee shall then distribute such amount to the Holders of such Separate
Senior Notes.

     SECTION 306. Additional Event of Default. In addition to the events listed
as Events of Default in Section 501 of the Original Indenture, it shall be an
additional Event of Default with respect to the Senior Notes, if the Company
shall not have satisfied its obligation to pay the Put Price when due in
accordance with Section 305 (either by payment of the Put Price to the Trustee
when due, by deposit of the Put Price in the Collateral Account when due or by
netting the Put

                                     - 11 -

<PAGE>

Price against a Holder's obligation under the related Purchase Contract if a
Senior Note is a component of a Corporate Unit).

                                    ARTICLE 4

                              TAX TREATMENT SECTION

     SECTION 401. Tax Treatment. The Company agrees, and by acceptance of a
Corporate Unit, each holder of a Corporate Unit will be deemed to have agreed
(a) for United States federal, state and local income and franchise tax purposes
to treat the acquisition of a Corporate Unit as the acquisition of the Senior
Note and the Purchase Contract constituting the Corporate Unit and (b) to treat
the Senior Note as indebtedness for United States federal, state and local
income and franchise tax purposes. A Holder of Senior Notes may obtain the
comparable yield and projected payment schedule for the Senior Notes, determined
by the Company pursuant to Treas. Reg. Sec. 1.1275-4, by submitting a written
request for such information to the Company at the following address: ONEOK,
Inc., 100 West Fifth Street, Tulsa, Oklahoma 74103, Attention: Chief Financial
Officer.

                                    ARTICLE 5

                             ORIGINAL ISSUE DISCOUNT

     SECTION 501. Original Issue Discount. The Company shall file with the
Trustee promptly at the end of each calendar year (i) a written notice
specifying the amount of original issue discount (including daily rates and
accrual periods) accrued on Senior Notes that are outstanding as of the end of
the year and (ii) such other specific information relating to such original
issue discount as may then be relevant under the Internal Revenue Code of 1986,
as amended from time to time.

                                    ARTICLE 6

                            MISCELLANEOUS PROVISIONS

     SECTION 601. Recitals by Company. The recitals in this First Supplemental
Indenture are made by the Company only and not by the Trustee, and all of the
provisions contained in the Original Indenture in respect of the rights,
privileges, immunities, powers and duties of the Trustee shall be applicable in
respect of Senior Notes and of this First Supplemental Indenture as fully and
with like effect as if set forth herein in full.

     SECTION 602. Ratification and Incorporation of Original Indenture. The
Original Indenture is in all respects ratified and confirmed, and the Original
Indenture and this First Supplemental Indenture shall be read, taken and
construed as one and the same instrument; provided that, in the case of a
conflict between this First Supplemental Indenture and the Original Indenture,
this First Supplemental Indenture shall control.

     SECTION 603. Executed in Counterparts. This First Supplemental Indenture
may be simultaneously executed in several counterparts, each of which shall be
deemed to be an original, and such counterparts shall together constitute one
and the same instrument.

                                     - 12 -

<PAGE>

     SECTION 604. Parties Interested Herein. Nothing in the Indenture expressed
or implied is intended or shall be construed to confer upon, or to give or grant
to, any person or entity, other than the Company, the Trustee, the Paying Agent,
the Custodial Agent, the Purchase Contract Agent, the Security Registrar, the
Collateral Agent and the registered owners of the Senior Notes, any right,
remedy or claim under or by reason of the Indenture or any covenant, condition
or stipulation hereof, and all covenants, stipulations, promises and agreements
in the Indenture contained by and on behalf of the Company shall be for the sole
and exclusive benefit of the Company, the Trustee, the Paying Agent, the
Custodial Agent, the Purchase Contract Agent, the Security Registrar, the
Collateral Agent and the registered owners of the Senior Notes.

                  [remainder of page intentionally left blank]

                                     - 13 -

<PAGE>

     IN WITNESS WHEREOF, each party hereto has caused this First Supplemental
Indenture to be signed in its name and behalf by its duly authorized officer or
signatory, all as of the day and year first above written.

                                        ONEOK, INC.


                                        By: /s/ Jim Kneale
                                            ------------------------------------
                                        Name:   Jim Kneale
                                              ----------------------------------
                                        Title:  Senior Vice President, Treasurer
                                                and Chief Financial Officer
                                                --------------------------------



                                        SUNTRUST BANK, as Trustee


                                        By: /s/ George Hogan
                                            ------------------------------------
                                                Authorized Signatory

                                     - 14 -

<PAGE>

                                                                       EXHIBIT A

                               FORM OF SENIOR NOTE

                                   [Attached]

<PAGE>

     [IF THIS SENIOR NOTE IS TO BE A GLOBAL SECURITY INSERT:] THIS SENIOR NOTE
IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO
AND IS REGISTERED IN THE NAME OF A DEPOSITORY OR A NOMINEE THEREOF. THIS SENIOR
NOTE MAY NOT BE EXCHANGED IN WHOLE OR IN PART FOR A SECURITY REGISTERED, AND NO
TRANSFER OF THIS SENIOR NOTE IN WHOLE OR IN PART MAY BE REGISTERED, IN THE NAME
OF ANY PERSON OTHER THAN SUCH DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED
CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

     UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE ISSUER OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), 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.


                                   ONEOK, INC.
                           4.0% SENIOR NOTES DUE 2008

                               CUSIP: 682680 40 0

No. ___                                                             $___________

     ONEOK, Inc., an Oklahoma corporation (herein called the "Company," which
term includes any successor corporation under the Indenture referred to herein),
for value received, hereby promises to pay to:

     [CEDE & CO.][SUNTRUST BANK]

or registered assigns, the principal sum of up to

     *__________________________ DOLLARS,* ($_________________)

     as set forth in the Schedule of Increases or Decreases In Senior Note
attached hereto, on February 16, 2008 (such date is hereinafter referred to as
the "Maturity Date"), and to pay interest thereon from January 28, 2003 or from
the most recent Interest Payment Date to which interest has been paid or duly
provided for, quarterly in arrears on February 16, May 16, August 16 and
November 16 of each year (each, an "Interest Payment Date"), commencing May 16,
2003, at the rate of 4.0% per annum through and including the day immediately
preceding the

<PAGE>

Reset Effective Date, if any, and thereafter at the Reset Rate, if any, on the
basis of a 360-day year consisting of twelve 30-day months, until the principal
hereof is paid or duly provided for or made available for payment, and (to the
extent that the payment of such interest shall be legally enforceable) to pay
interest, compounded quarterly, at the rate of 4.0% per annum on any overdue
principal and payment of interest through and including the day immediately
preceding the Reset Effective Date, if any, and thereafter at the Reset Rate, if
any. The Reset Rate, if any, shall be established pursuant to the terms of the
Indenture and the Remarketing Agreement. The amount of interest payable for any
period shorter than a full quarterly period for which interest is computed will
be computed on the basis of a 30-day month and, for any period less than a
month, on the basis of the actual number of days elapsed per 30-day month.

     Any such interest not so punctually paid or duly provided for shall
forthwith cease to be payable to the Holder on such Regular Record Date by
virtue of his having been such Holder, and may be paid to the Holder of record
of this Senior Note at the close of business on a special record date (the
"Special Record Date") fixed by the Company for the payment of such defaulted
interest, notice whereof shall be given to Holders not less than ten days prior
to such Special Record Date, all as more fully provided in the Indenture.

     Payment of the principal of this Senior Note and the interest thereof will
be made at the office or agency of the Company in the Borough of Manhattan, City
and State of New York or at the Corporate Trust Office of the Trustee in such
currency of the United States of America as at the time of payment is legal
tender for payment of public and private debts; provided, however, that payment
of interest may be made at the option of the Company by check mailed to the
Holder at such address as shall appear in the Security Register or by wire
transfer to an account appropriately designated by the Holder entitled to
payment.

     Reference is hereby made to the further provisions of this Senior 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.

<PAGE>

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Senior Note
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

     IN WITNESS WHEREOF, the Company has caused this Senior Note to be duly
executed under its corporate seal.

                                        ONEOK, INC.


                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------


                                        Attested:
                                                  ------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------


                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION


This is one of the Senior Notes referred to in the within-mentioned Indenture

                                        SUNTRUST BANK, as Trustee


                                        By:
                                            ------------------------------------
                                                    Authorized Signatory


Dated: January 28, 2003

<PAGE>

                             REVERSE OF SENIOR NOTE

                                   ONEOK, INC.
                           4.0% Senior Notes due 2008

     This Senior Note is one of a duly authorized issue of securities of the
Company (herein called the "Senior Notes"), issued and to be issued in one or
more series under an Indenture, dated as of December 28, 2001, between the
Company and SunTrust Bank, as Trustee, (herein called the "Trustee", which term
includes any successor trustee) (the "Original Indenture"), as amended and
supplemented by the First Supplemental Indenture, dated January 28, 2003,
between the Company and the Trustee (the "Supplemental Indenture" and, together
with the Original Indenture, the "Indenture"), to which Indenture reference is
hereby made for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee and the Holders of
the Senior Notes and of the terms upon which the Senior Notes are, and are to
be, authenticated and delivered. This Senior Note is one of the series
designated on the face hereof, limited in aggregate principal amount to
$350,000,000 (plus up to an additional $52,500,000 to the extent the
underwriters' over-allotment option is exercised).

     If a Special Event shall occur and be continuing, the Company may, at its
option, redeem the Senior Notes of this series in whole, but not in part, on any
Interest Payment Date prior to the earlier of the date of a Successful
Remarketing or the Purchase Contract Settlement Date, at a price per Senior Note
equal to the Redemption Price as set forth in the Supplemental Indenture.

     If there has not been a Successful Remarketing prior to the Purchase
Contract Settlement Date, the Holders of Senior Notes will have the right to
require the Company to purchase their Senior Notes on the Purchase Contract
Settlement Date, all as more fully described in the Supplemental Indenture.

     The Senior Notes are not entitled to the benefit of any sinking fund and
will not be subject to defeasance. The Company shall not be obligated to pay
Additional Amounts, as contemplated by Section 1008 of the Original Indenture,
on the Senior Notes to any Holder who is not a United States person.

     If an Event of Default (as defined in the Indenture) with respect to the
Senior Notes shall occur and be continuing, the principal of the Senior Notes
plus any accrued interest may be declared due and payable in the manner and with
the effect and subject to the conditions provided in the Indenture.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders under the Indenture at any time by the
Company and the Trustee with the consent of the Holders of a majority in
aggregate principal amount of the Senior Notes then Outstanding (as defined in
the Indenture) of all series that are affected by such amendment or
modification, except that certain amendments that do not adversely affect the
rights of the Holders of the Senior Notes may be made without the approval of
Holders of the Senior Notes. No amendment or modification may, among other
things, change the Stated Maturity of any Senior Note, reduce the principal
amount thereof, reduce the rate or change the time of payment of any interest

<PAGE>

thereon, or reduce the percentage in principal amount of the Senior Notes,
consent of the Holders of which is required for any such amendment or
modification, without the consent of each Holder of Senior Notes affected.

     Notwithstanding any provision in the Indenture or any provision of this
Senior Note, the Holder of this Senior Note shall have the right, which is
absolute and unconditional, to receive payment of the principal of (and premium,
if any) and interest on this Senior Note at the times, places and rate, and in
the currency herein prescribed.

     As provided in the Indenture and subject to certain limitations therein set
forth, the transfer of this Senior Note is registrable in the Securities
Register, upon surrender of this Senior Note for registration of transfer at the
office or agency of the Company in any place where the principal of and interest
on this Senior Note are payable, duly endorsed by, or accompanied by a written
instrument of transfer in form satisfactory to the Company and the Securities
Registrar duly executed by the Holder hereof or his attorney duly authorized in
writing, and thereupon one or more new Senior Notes of this series, of
authorized denominations and for the same aggregate principal amount, will be
issued to the designated transferee or transferees.

     The Senior Notes of this series are issuable only in registered form
without coupons in denominations of $25.00 and any integral multiple thereof. As
provided in the Indenture and subject to certain limitations therein set forth,
Senior Notes of this series are exchangeable for a like aggregate principal
amount of Senior Notes of this series of a different authorized denomination, as
requested by the Holder surrendering the same.

     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 Senior 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 Senior Note is registered as the owner hereof for
all purposes, whether or not this Senior Note be overdue, and neither the
Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

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

     The Company agrees, and by acceptance of the Senior Notes, each Holder of
Senior Notes will be deemed to have agreed (1) for United States federal, state
and local income and franchise tax purposes to treat the acquisition of a
Corporate Unit as the acquisition of the Senior Note and the Purchase Contract
constituting the Corporate Unit and (2) to treat the Senior Note as indebtedness
for United States federal, state and local income and franchise tax purposes. A
Holder of Senior Notes may obtain the comparable yield and projected payment
schedule for the Senior Notes, determined by the Company pursuant to Treas. Reg.
Sec. 1.1275-4, by submitting a written request for it to the Company at the
following address: ONEOK, Inc., 100 West Fifth Street, Tulsa, Oklahoma 74103,
Attention: Chief Financial Officer.

<PAGE>

     THIS SENIOR NOTE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF
LAW THEREOF.

<PAGE>

                SCHEDULE OF INCREASES OR DECREASES IN SENIOR NOTE

     The initial principal amount of this Senior Note is $350,000,000. The
following increases or decreases in a part of this Senior Note have been made:

<TABLE>
<CAPTION>
                  Amount of decrease          Amount of increase           Principal Amount of this
                  in principal amount         in principal amount         Senior Note following such       Signature of authorized
    Date          of this Senior Note         of this Senior Note            decrease or increase             officer of Trustee
------------   -------------------------   -------------------------   --------------------------------   -------------------------
<S>            <C>                         <C>                         <C>                                <C>

</TABLE>

<PAGE>

                                 ASSIGNMENT FORM

               To assign this Senior Note, fill in the form below:
      For value received, I or we assign and transfer this Senior Note to:

                          ____________________________

                          ____________________________


                   Insert assignee's soc. sec. or tax I.D. no.

                          ____________________________


________________________________________________________________________________
              (Print or type assignee's name, address and zip code)


________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
and all rights thereunder and irrevocably appoint ______________________________
________________________________________________________________________________
agent to transfer this Senior Note on the books of the Company. The agent may
substitute another to act for him.


                                        Signature:


Dated:
       -------------------              ----------------------------------------


                   Signature Guarantee:
                                        ----------------------------------------


     THE SIGNATURE TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME AS IT
APPEARS ON THE FIRST PAGE OF THE SENIOR NOTE.

     THE SIGNATURE MUST BE GUARANTEED BY AN "ELIGIBLE GUARANTOR INSTITUTION"
THAT IS A MEMBER OR PARTICIPANT IN A "SIGNATURE GUARANTEE PROGRAM" (e.g., THE
SECURITIES TRANSFER AGENTS MEDALLION PROGRAM, THE STOCK EXCHANGE MEDALLION
PROGRAM OR THE NEW YORK STOCK EXCHANGE, INC. MEDALLION PROGRAM).