As filed with the Securities and Exchange Commission on June 8, 2006
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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 10-K/A

                                (Amendment No. 1)
 (Mark One)

|X|    ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
       ACT OF 1934

        For the fiscal year ended December 31, 2005

                                       OR

|_|    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
       EXCHANGE ACT OF 1934

        For the transition period from _____________ to ______________

                           Commission File No. 0-19341

                            BOK FINANCIAL CORPORATION
             (Exact name of registrant as specified in its charter)


                Oklahoma                                   73-1373454
      (State or other jurisdiction                       (IRS Employer
    of Incorporation or Organization)                 Identification No.)

         Bank of Oklahoma Tower
              P.O. Box 2300
             Tulsa, Oklahoma                                  74192
(Address of Principal Executive Offices)                    (Zip Code)

                                 (918) 588-6000
              (Registrant's telephone number, including area code)

          Securities registered pursuant to Section 12 (b) of the Act:
                                      None

          Securities registered pursuant to Section 12 (g) of the Act:
                        Common stock, $0.00006 par value

     Indicate by check mark if the registrant is a well-known  seasoned  issuer,
as defined in Rule 405 of the Securities Act. Yes |X| No |_|

     Indicate by check mark if the  registrant  is not  required to file reports
pursuant to Section 13 or Section 15 (d) of the Act. Yes |_| No |X|

     Indicate  by check mark  whether the  registrant  (1) has filed all reports
required to be filed by Section 13 or 15(d) of the  Securities  Exchange  Act of
1934  during  the  preceding  12 months  (or for such  shorter  period  that the
registrant was required to file such reports),  and (2) has been subject to such
filing requirements for the past 90 days. Yes |X| No |_|

     Indicate by check mark if disclosure of delinquent  filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's  knowledge,  in definitive proxy or information  statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. |_|

     Indicate by check mark whether the registrant is a large accelerated filer,
an accelerated filer, or a non-accelerated filer. See definition of "accelerated
filer and large  accelerated  filer" in Rule 12b-2 of the Exchange  Act.  (Check
one):
Large accelerated filer |X| Accelerated  filer |_|  Non-accelerated  filer  |_|

     Indicate  by check mark  whether  the  registrant  is a shell  company  (as
defined in Rule 12b-2 of the Act). Yes |_| No |X|

     The  aggregate  market  value of the  registrant's  common  stock  ("Common
Stock") held by non-affiliates is approximately  $948,181,172 (based on the June
30, 2005  closing  price of Common  Stock of $46.12 per  share).  As of March 1,
2006, there were 66,955,508 shares of Common Stock outstanding.

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                                EXPLANATORY NOTE

     BOK Financial Corporation (the "Company") is filing this Amendment No. 1 on
Form  10-K/A to amend its Annual  Report on Form 10-K for the fiscal  year ended
December  31,  2005  as  originally  filed  with  the  Securities  and  Exchange
Commission (the  "Commission")  on March 15, 2006 (the "Original Form 10-K") for
the sole purpose of  correcting a mistaken  reference to the date of the Reports
of Ernst & Young LLP as March 1, 2006 instead of March 10, 2006.  The  corrected
dates have been included in Exhibits 99(a) and 99(b) attached hereto.  There are
no changes to the Company's financial  statements as originally filed. There are
also no changes to the  disclosures  in the Original Form 10-K,  and the Company
has not  updated  the  disclosure  contained  herein to reflect  any events that
occurred at a later date.

     The date  references in the Company's  Annual  Report to  Shareholders  are
correct as originally printed.


ITEM 8 - FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

     Included  as Exhibit 99 (a) and  Exhibit 99 (b) to this Form 10-K/A are the
Report of Ernst & Young LLP,  Independent  Registered Public Accounting Firm, on
the BOK Financial Corporation  consolidated  financial statements as of December
31, 2005 and 2004, and the related statements of earnings, shareholders' equity,
and cash flows for each of the three  years in the  period  ended  December  31,
2005,  and the  Report on  Effectiveness  of  Internal  Control  Over  Financial
Reporting as of December 31, 2005, respectively.

     These reports have been revised  solely to reference a report date of March
10, 2006 within the final  paragraph of each report,  instead of the  previously
referenced March 1, 2006.

     The date  references in the Company's  Annual  Report to  Shareholders  are
correct as originally printed.


ITEM 15 - EXHIBITS, FINANCIAL STATEMENT SCHEDULES

     Item 15  beginning  on page 17 of the  Annual  Report  on Form 10-K for the
fiscal year ended  December 31, 2005 is amended by  substituting  the  following
revised exhibits:

Exhibit 23.0    Consent of independent registered public accounting
                firm - Ernst & Young LLP.

Exhibit 99 (a)  Report of Ernst & Young LLP, Independent Registered Public
                Accounting Firm, on Consolidated Financial Statements.

Exhibit 99 (b)  Report of Ernst & Young LLP, Independent Registered Public
                Accounting Firm, on Effectiveness of Internal Control over
                Financial Reporting.



                                   SIGNATURES

Pursuant to the  requirements of Section 13 or 15(d) of the Securities  Exchange
Act of 1934,  the  registrant  has duly  caused  this report to be signed on its
behalf by the undersigned, thereunto duly authorized.

                                                BOK FINANCIAL CORPORATION




DATE:    June 8, 2006                      BY:  /s/ Stanley A. Lybarger
      ------------------------------           --------------------------------
                                               Stanley A. Lybarger
                                               Director, President and Chief
                                               Executive Officer


                                                /s/ Steven E. Nell
                                               --------------------------------
                                               Steven E. Nell
                                               Executive Vice President and
                                               Chief Financial Officer


                                                /s/ John C. Morrow
                                               --------------------------------
                                               John C. Morrow
                                               Senior Vice President and
                                               Director of Financial Accounting
                                               and Reporting