|   | (Date of report)                  | June 7, 2011 |
|--------|-----------------------------------|--------------|
|   | (Date of earliest event reported) | June 7, 2011 |

| Delaware                     |   | 1-12202      |   | 93-1120873          |
|------------------------------|--------|--------------|--------|---------------------|
| (State or other jurisdiction |   | (Commission  |   | (IRS Employer       |
| of incorporation)            |   | File Number) |   | Identification No.) |

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| Item 8.01 |   | Other Events                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-----------|--------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|      |   |  On June 7, 2011, we issued a news release announcing a two-for-one split of our outstanding units.  The two-for-one split will be effected by a distribution of one unit for each unit outstanding and held by holders of record on June 30, 2011.  The two-for-one unit split is expected to be completed on July 12, 2011.  A copy of the news release is attached to this Current Report as Exhibit 99.1.   |
| Item 9.01 |   | Financial Statements and Exhibits                                                                                                                                                                                                                                                                                                                                                                                                                            |
|      |   |  Exhibits                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|      |   | 99.1   News release of ONEOK Partners, L.P. dated June 7, 2011, announcing declaration of unit split.                                                                                                                                                                                                                                                                                                                                         |
|      |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                         |

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|   |         |   | ONEOK Partners, L.P.By:  ONEOK Partners GP, L.L.C.,General Partner          |
|--------|--------------|--------|---------------------------------------------------------------------------------------|
|   |         |   |                                                                                  |
| Date:  | June 7, 2011 | By:    | /s/ Robert F. Martinovich                                                             |
|   |         |   | Robert F. MartinovichSenior Vice President,Chief Financial Officer andTreasurer  |

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