Exhibit 3.1

                            CERTIFICATE OF AMENDMENT
                                       TO
                       CERTIFICATE OF LIMITED PARTNERSHIP
                                       OF
                         NORTHERN BORDER PARTNERS, L.P.

The undersigned, desiring to amend the Certificate of Limited Partnership of
Northern Border Partners, L.P. (the "Certificate of Limited Partnership")
pursuant to the provisions of Section 17-202 of the Revised Uniform Limited
Partnership Act of the State of Delaware, does hereby certify as follows:

    1.  The name of the limited partnership is: Northern Border Partners, L.P.

    2.  Paragraph 1 of the Certificate of Limited Partnership is hereby deleted
        in its entirety and replaced with the following:

            "1. The name of the limited partnership is: ONEOK Partners, L.P."

    3.  Paragraph 3 of the Certificate of Limited Partnership is hereby deleted
        in its entirety and replaced with the following:

            "3. The name and mailing address of each general partner is as
                follows:

                  Name                                Mailing Address
                  ----                                ---------------

                  ONEOK Partners GP, L.L.C.           100 West 5th Street
                                                      Tulsa, OK 74103"



                  [Remainder of Page Intentionally Left Blank]

This Certificate of Amendment is executed as of the 17th day of May, 2006.


                                       ONEOK Partners GP, L.L.C., sole
                                       general partner

                                       By:   /s/ David Kyle
                                          ------------------------------
                                       David Kyle, Chairman and
                                       Chief Executive Officer