
<PAGE>

                                                                  Exhibit 4.4(b)
                                TRUST AGREEMENT
                                ---------------

     This TRUST AGREEMENT, dated as of ________, 1999 (this "Trust Agreement"),
among (i) ONEOK, INC., an Oklahoma corporation (the "Depositor"), (ii)         ,
a Delaware corporation (the "Delaware Trustee"), and (iii)                  , a
national banking association (the "Property Trustee") (collectively with the
Delaware Trustee, the "Trustees"). The Depositor and the Trustees hereby agree
as follows:

     1.   The trust  created  hereby  (the  "Trust")  shall be known as "ONEOK
CAPITAL  TRUST II" in which name the  Trustees,  or the  Depositor to the extent
provided herein, may engage in the transactions  contemplated  hereby,  make and
execute contracts, and sue and be sued.

     2.   The Depositor hereby assigns, transfers, conveys and sets over to the
Trust the sum of $10. The Trustees hereby acknowledge receipt of such amount
from the Depositor, which amount shall constitute the initial trust estate. The
Trustees hereby declare that they will hold the trust estate for the Depositor.
It is the intention of the parties hereto that the Trust created hereby
constitutes a business trust under Chapter 38 of Title 12 of the Delaware Code,
12 Del. C. (S) 3801, et seq. (the "Business Trust Act"), and that this document
   -------           ------
constitutes the governing instrument of the Trust. The Trustees are hereby
authorized and directed to execute and file a certificate of trust with the
Delaware Secretary of State in accordance with the provisions of the Business
Trust Act.

     3.   The Depositor, the Trustees and certain other trustees to be
hereafter appointed will enter into an amended and restated Trust Agreement,
satisfactory to each such party and substantially in the form included as an
exhibit to the 1933 Act Registration Statement (as defined below), to provide
for the contemplated operation of the Trust created hereby and the issuance of
the Preferred Securities and Common Securities referred to therein. Prior to the
execution and delivery of such amended and restated Trust Agreement, the
Trustees shall not have any duty or obligation hereunder or with respect to the
trust estate, except as otherwise required by applicable law or as may be
necessary to obtain prior to such execution and delivery any licenses, consents
or approvals required by applicable law or otherwise.

     4.   The Depositor and the Trustees hereby authorize and direct the
Depositor, as the Depositor of the Trust, (i) to file with the Securities and
Exchange Commission (the "Commission") and execute, in each case on behalf of
the Trust, (a) the Registration Statement on Form S-3 (the "1933 Act
Registration Statement"), including any pre-effective or post-effective
amendments to the 1933 Act Registration Statement, relating to the registration
under the Securities Act of 1933, as amended (the "1933 Act"), of the Preferred
Securities of the Trust and certain other securities, (b) any Prospectus or
Preliminary Prospectus relating to the Preferred Securities required to be filed
under the 1933 Act, and (c) a Registration Statement on Form 8-A (the "1934 Act
Registration Statement") (including all pre-effective and post-effective
amendments thereto) relating to the registration of the Preferred Securities of
the Trust under the Securities Exchange Act of 1934, as amended; (ii) to file
with the New York Stock Exchange or any other national stock exchange or The
Nasdaq National Market (each, an "Exchange") and execute on behalf of the Trust
one or more listing applications and all other applications, statements,
certificates, agreements and other instruments as shall be necessary or
desirable to cause the Preferred Securities to be listed on any of the
Exchanges; (iii) to file and execute on behalf of the Trust such applications,
reports, surety bonds, irrevocable consents, appointments of attorney for
service of process and other papers and documents as shall
<PAGE>

be necessary or desirable to register the Preferred Securities under the
securities or blue sky laws of such jurisdictions as the Depositor, on behalf of
the Trust, may deem necessary or desirable and (iv) to execute on behalf of the
Trust that certain Underwriting Agreement relating to the Preferred Securities,
among the Trust, the Depositor, and the several Underwriters named therein,
substantially in the form included as an exhibit to the 1933 Act Registration
Statement. In connection with the filings referred to above, the Depositor
hereby constitutes and appoints as its true and lawful attorneys-in-fact and
agents, with full power of substitution and resubstitution, for the Depositor or
in the Depositor's name, place and stead, in its capacity as Depositor of the
Trust, to sign any and all amendments (including post-effective amendments) to
the 1933 Act Registration Statement and the 1934 Act Registration Statement and
to file the same, with all exhibits thereto, and any other documents in
connection therewith, with the Commission, the Exchange and administrators of
state securities or blue sky laws, granting unto said attorneys-in-fact and
agents full power and authority to do and perform each and every act and thing
requisite and necessary to be done in connection therewith, as fully to all
intents and purposes as the Depositor might or could do in person, hereby
ratifying and confirming all that said attorneys-in-fact and agents or any of
them, or their respective substitute or substitutes, shall do or cause to be
done by virtue hereof.

     5.   This Trust Agreement may be executed in one or more counterparts.

     6.   The number of Trustees initially shall be two (2) and thereafter the
number of Trustees shall be such number as shall be fixed from time to time by a
written instrument signed by the Depositor which may increase or decrease the
number of Trustees; provided, however, that to the extent required by the
Business Trust Act, one Trustee shall either be a natural person who is a
resident of the State of Delaware or, if not a natural person, an entity which
has its principal place of business in the State of Delaware and otherwise meets
the requirements of applicable Delaware law. Subject to the foregoing, the
Depositor is entitled to appoint or remove without cause any Trustee at any
time. The Trustees may resign upon thirty (30) days' prior notice to the
Depositor.

     7.   This  Trust  Agreement  shall be  governed  by,  and  construed  in
accordance  with, the laws of the State of Delaware  (without regard to conflict
of laws principles).

     8.   The Delaware  Trustee  shall not have any of the powers or duties of
the Trustees set forth herein,  except as required under the Business Trust Act.
The  Delaware  Trustee  shall be a Trustee  hereunder  for the sole and  limited
purpose of fulfilling the requirements of (S) 3807(a) of the Business Trust Act.

                           [SIGNATURE PAGE FOLLOWS]

                                       2
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Trust Agreement to
be duly executed as of the day and year first above written.

                                ONEOK, INC., as Depositor

                                By:_____________________________________________
                                                                          Signed
                                this   day of    , 1999, in the City of    , the
                                State of


                                                                            , as
                                Trustee

                                By:_____________________________________________



                                                                            , as
                                Trustee

                                By:_____________________________________________


                                       3
