Exhibit 21

SUBSIDIARIES OF THE COMPANIES

Subsidiaries of ONEOK Partners Intermediate Limited Partnership:



|                                                             |  |               
|------------------------------------------------------------ |  | --------------
|ONEOK Partners Intermediate Limited Partnership              |  | Delaware      
|ONEOK ILP GP, L.L.C.                                         |  | Delaware      
|Bear Paw Investments, LLC.                                   |  | Delaware      
|Bear Paw Energy, LLC.                                        |  | Delaware      
|Bear Paw Processing Company (Canada), Ltd.                   |  | Alberta       
|Brown Bear Enterprises, LLC.                                 |  | Delaware      
|Border Minnesota Pipeline, LLC.                              |  | Delaware      
|Black Mesa Holdings, Inc.                                    |  | Delaware      
|Black Mesa Pipeline, Inc.                                    |  | Delaware      
|Black Mesa Pipeline Operations, L.L.C.                       |  | Delaware      
|Black Mesa Technologies, Inc.                                |  | Oklahoma      
|Black Mesa Technologies Services, LLC (60%)                  |  | Oklahoma      
|Border Midstream Services, Ltd.                              |  | Alberta       
|Border Midwestern Company                                    |  | Delaware      
|Midwestern Gas Marketing Company                             |  | Delaware      
|Midwestern Gas Transmission Company                          |  | Delaware      
|Border Viking Company                                        |  | Delaware      
|Viking Gas Transmission Company                              |  | Delaware      
|Crestone Energy Ventures, L.L.C.                             |  | Delaware      
|Crestone Bighorn, L.L.C.                                     |  | Delaware      
|Crestone Gathering Services, L.L.C.                          |  | Delaware      
|Crestone Powder River, L.L.C.                                |  | Delaware      
|Crestone Wind River, L.L.C.                                  |  | Delaware      
|Northern Border Pipeline Company (general partnership) (50%) |  | Texas         
|China Pipeline Holdings Ltd. (0.81%)                         |  | Cayman Islands
|Guardian Pipeline, L.L.C. (100%)                             |  | Delaware      
|Bighorn Gas Gathering, L.L.C. (49.0%)                        |  | Delaware      
|Fort Union Gas Gathering, LLC (37.04%)                       |  | Delaware      
|Lost Creek Gathering Company, L.L.C. (35%)                   |  | Delaware      
|Chisholm Pipeline Company (50%)                              |  | Delaware      
|Chisholm Pipeline Holdings, L.L.C.                           |  | Delaware      
|Mid Continent Market Center, L.L.C.                          |  | Kansas        
|OkTex Pipeline Company, L.L.C.                               |  | Delaware      
|ONEOK Field Services Company, L.L.C.                         |  | Oklahoma      
|ONEOK Gas Gathering, L.L.C.                                  |  | Oklahoma      
|ONEOK Gas Storage Holdings, L.L.C.                           |  | Delaware      
|ONEOK Gas Storage, L.L.C.                                    |  | Oklahoma      
|ONEOK Gas Transportation, L.L.C.                             |  | Oklahoma      
|ONEOK Hydrocarbon, L.L.C.                                    |  | Delaware      
|ONEOK Hydrocarbon, L.P.                                      |  | Delaware      
|ONEOK Hydrocarbon GP, L.L.C.                                 |  | Delaware      



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|                                                        |  |         
|------------------------------------------------------- |  | --------
|ONEOK Hydrocarbon Holdings, L.L.C.                      |  | Delaware
|ONEOK Hydrocarbon Southwest, L.L.C.                     |  | Delaware
|ONEOK MB I, L.P.                                        |  | Delaware
|ONEOK Midstream Gas Supply, L.L.C.                      |  | Oklahoma
|ONEOK Mont Belvieu Storage Company, L.L.C.              |  | Oklahoma
|ONEOK NGL Pipeline, L.P.                                |  | Delaware
|ONEOK Overland Pass Holdings, L.L.C.                    |  | Oklahoma
|ONEOK Pipeline Holdings, L.L.C.                         |  | Delaware
|ONEOK Sayre Storage Company, L.L.C.                     |  | Delaware
|ONEOK Texas Gas Storage, L.P.                           |  | Texas   
|ONEOK Transmission Company, L.L.C.                      |  | Delaware
|ONEOK Underground Storage Company, L.L.C.               |  | Kansas  
|ONEOK VESCO Holdings, L.L.C.                            |  | Delaware
|ONEOK WesTex Transmission, L.P.                         |  | Delaware
|Overland Pass Pipeline Company LLC.                     |  | Delaware
|Potato Hills Gas Gathering System (joint venture) (51%) |  | Oklahoma
|Sycamore Gas System (general partnership) (48.445%)     |  | Oklahoma
|Venice Energy Services Company, LLC (10.1765%)          |  | Delaware
|Mont Belvieu I Fractionation Facility (joint venture)   |  | Texas