<PAGE>
 
As filed with the Securities and Exchange Commission on September 30, 1998
                                                           REGISTRATION NO. 333-
================================================================================
                                        
                       SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549

                                    FORM S-8

            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                             BANCFIRST CORPORATION
             (Exact name of Registrant as specified in its charter)

                                    OKLAHOMA
         (State or other jurisdiction of incorporation or organization)

          6022                                                   73-1221379
(Primary Standard Industrial                                  (I.R.S. Employer
 Classification Code Number)                                 Identification No.)

                         101 North Broadway, Suite 200
                         Oklahoma City, Oklahoma 73102
                                 (405) 270-1086
  (Address, including zip code, and telephone number, including area code, of
                   Registrants' principal executive offices)

           1988 Incentive Stock Option Plan of Security Corporation
                      as assumed by BancFirst Corporation
 
           1993 Incentive Stock Option Plan of Security Corporation
                      as assumed by BancFirst Corporation
 
       1995 Non-Employee Director Stock Plan of AmQuest Financial Corp.
                      as assumed by BancFirst Corporation
                          (Full titles of the plans)
 
                               David E. Rainbolt
                     President and Chief Executive Officer
                             BancFirst Corporation
                         101 North Broadway, Suite 200
                         Oklahoma City, Oklahoma 73102
                                (405) 270-1086
          (Name, address, including zip code, and telephone number, 
                  including area code, of agents for service)

 
                                  COPIES TO:
                           JEANETTE C. TIMMONS, ESQ.
              Day Edwards Federman Propester & Christensen, P.C.
                              2900 Oklahoma Tower
                                210 Park Avenue
                         Oklahoma City, Oklahoma 73102
                                (405) 239-2121

                        CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
====================================================================================================================================

    TITLE OF EACH CLASS OF              AMOUNT TO BE        PROPOSED MAXIMUM         PROPOSED MAXIMUM AGGREGATE     AMOUNT OF
 SECURITIES TO BE REGISTERED            REGISTERED (1)  OFFERING PRICE PER SHARE (2)     OFFERING PRICE (2)     REGISTRATION FEE (3)

- ------------------------------------------------------------------------------------------------------------------------------------

<S>                                     <C>             <C>                          <C>                        <C>
Common Stock, $0.01 par value per share    116,461               $37.75                       $4,396,403              $1,297
====================================================================================================================================

</TABLE>

(1)  Pursuant to Rule 416(a), also covers additional securities that may be
     offered as a result of stock splits, stock dividends or similar
     transactions.
(2)  Estimated solely for the purpose of determining the registration fee and
     calculated pursuant to Rule 457(c) based upon the average of the high and
     low prices of the Common Stock on the Nasdaq National Market on September
     29, 1998, which was $37.75.
(3)  The registration fee was calculated pursuant to Rule 457(c), as $295 per $1
     million.
 
<PAGE>
 
                                  INTRODUCTION

     This Registration Statement on Form S-8 is filed by BancFirst Corporation,
an Oklahoma corporation (the "Company," BancFirst or the "Registrant"), relating
to an aggregate 116,461 shares of its common stock, par value $1.00 per share
(the "Common Stock") issuable under the 1988 Incentive Stock Option Plan of
Security Corporation, the 1993 Incentive Stock Option Plan of Security
Corporation and the 1995 Non-Employee Director Stock Option Plan of AmQuest
Financial Corp., all of which have been assumed by BancFirst pursuant to the
Merger Agreement dated May 6, 1998 between BancFirst and AmQuest Financial Corp.
(collectively, the "Plans").

                                     PART I
                                        
                INFORMATION REQUIRED IN SECTION 10(a) PROSPECTUS
                                        
ITEM 1.  PLAN INFORMATION.

     Not filed as part of this Registration Statement pursuant to Note to Part 1
of Form S-8.

ITEM 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.

     Not filed as part of this Registration Statement pursuant to Note to Part 1
of Form S-8.

                                    PART II
                                        
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
                                        
ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents, which previously have been filed by the Company
with the Securities and Exchange Commission (the "Commission"), are incorporated
herein by reference and made a part hereof:

     (i)    The Company's latest Annual Report on Form 10-K for the fiscal year
            ended December 31, 1997;

     (ii)   All other reports filed pursuant to Section 13(a) or 15(d) of the
            Securities Exchange Act of 1934 (the "Exchange Act") since the end
            of the fiscal year covered by the Annual Report referred to in (i)
            above; and

     (iii)  The description of the Company's Common Stock contained in the
            Company's Registration Statement on Form 8A/A (Registration No. 
            000-14384), filed with the Commission on July 24, 1998, including
            any amendment or reports filed for the purpose of updating such
            description.

     All reports and other documents filed by the Company pursuant to Sections
13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of this
Registration Statement and prior to the filing of a post-effective amendment
hereto, which indicates that all securities offered hereunder have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference herein and to be a part hereof from the date of filing
of such documents.

     For purposes of this Registration Statement, any document or any statement
contained in a document incorporated or deemed to be incorporated herein by
reference shall be deemed to be modified or superseded to the extent that a
subsequently filed document or a statement contained herein or in any other
subsequently filed document which also is or is deemed to be incorporated herein
by reference modifies or supersedes such document or such statement in such
document.  Any statement so modified or superseded shall not be deemed, except
as so modified or superseded, to constitute a part of this Registration
Statement.

                                     II-2
<PAGE>
 
ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 1006(B)(7) of the General Corporation Act of the State of Oklahoma
(the "OGCA") authorizes a corporation in its certificate of incorporation to
eliminate or limit the personal liability of members of its board of directors
to the corporation or its stockholders for monetary damages for violations of a
director's fiduciary duty of care, including acts constituting gross negligence.
Such a provision would have no effect on the availability of equitable remedies,
such as an injunction or rescission, for breach of fiduciary duty.  In addition,
no such provision may eliminate or limit the liability of a director for
breaching his duty of loyalty to the corporation or its shareholders, failing to
act in good faith, engaging in intentional misconduct or knowingly violating a
law, paying an unlawful dividend or approving an illegal stock repurchase, or
executing any transaction from which the director obtained an improper personal
benefit.

     Section 1031 of the OGCA empowers a corporation to indemnify any person who
was or is a party to or is threatened to be made a party to any threatened,
pending or completed action, suit or proceeding, whether civil, criminal,
administrative or investigative (other than an action by or in the right of the
corporation), by reason of the fact that he is or was a director, officer,
employee or agent of the corporation, or is or was serving at the request of the
corporation as a director, officer, employee or agent of another corporation,
partnership, joint venture, trust or other enterprise, against expenses
(including attorney's fees), judgments, fines and amounts paid in settlement
actually and reasonably incurred by him in connection with such action, suit or
proceeding if he acted in good faith and in a manner he reasonably believed to
be in or not opposed to the best interests of the corporation, and, with respect
to any criminal action or proceeding, had no reasonable cause to believe his
conduct was unlawful.  With respect to actions or suits by or in the right of
the corporation, such indemnification is limited to expenses (including
attorneys' fees) actually and reasonably incurred by such person in connection
with the defense or settlement of such action or suit.  Further, no
indemnification shall be made in respect of any claim, issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the court in which such action or suit was
brought shall determine upon application that, despite the adjudication of
liability but in view of all the circumstances of the case, such person is
fairly and reasonably entitled to indemnity for such expenses which the court
shall deem proper.  Additionally, a corporation is required to indemnify its
directors and officers against expenses to the extent that such directors or
officers have been successful on the merits or otherwise in defense of any
action, suit or proceeding referred to above or in defense of any claim, issue
or matter therein.

     An indemnification can be made by the corporation only upon a determination
made in the manner prescribed by the statute that indemnification is proper in
the circumstances because the party seeking indemnification has met the
applicable standard of conduct as set forth in the OGCA.  The indemnification
provided by the OGCA shall not be deemed exclusive of any other rights to which
those seeking indemnification may be entitled under any bylaw, agreement, vote
of stockholders or disinterested directors, or otherwise.  A corporation also
has the power to purchase and maintain insurance on behalf of any person
covering any liability incurred by such person in his capacity as a director,
officer, employee or agent of the corporation, or arising out of his status as
such, whether or not the corporation would have the power to indemnify him
against such liability.  The indemnification provided by the OGCA shall, unless
otherwise provided when authorized or ratified, continue as to a person who has
ceased to be a director, officer, employee or agent and shall inure to the
benefit of the heirs, executors and administrators of such a person.

                                     II-3
<PAGE>
 
THE COMPANY'S CHARTER AND BYLAW PROVISIONS

     The Company's Amended and Restated Certificate of Incorporation (i) limits
its directors' liability for monetary damages to the Company and its
shareholders for breach of fiduciary duty except under the circumstances
outlined in Section 1006(B)(7) of the OGCA as described above, (ii) provides for
elimination or limitation of liability to the fullest extent permitted should
the OGCA be amended to authorize corporation action further eliminating or
limiting the personal liability of directors and (iii) provides for
indemnification to the fullest extent permitted by Section 1031 of the OGCA.

OTHER ARRANGEMENTS

     The Company maintains a directors' and officers' liability insurance policy
insuring its directors and officers against certain liabilities and expenses
incurred by them in their capacities as such and insuring the Company, under
certain circumstances, in the event that indemnification payments are made by
the Company to such directors and officers.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

Not applicable.

ITEM 8.  EXHIBITS.

     Unless otherwise indicated below as being incorporated by reference to
another filing of the Company with the Commission, each of the following
exhibits is filed herewith:


  Exhibit
   Number                           Name of Exhibit
   ------                           ---------------
 
      4.1  1988 Incentive Stock Option Plan of Security Corporation as assumed
           by BancFirst Corporation.
 
      4.2  1993 Incentive Stock Option Plan of Security Corporation as assumed
           by BancFirst Corporation.
 
      4.3  1995 Non-Employee Director Stock Plan of AmQuest Financial Corp. as
           assumed by BancFirst Corporation.
 
      5.1  Opinion of Day, Edwards, Federman, Propester & Christensen, P.C. as
           to the legality of the BancFirst Common Stock.
 
     23.1  Consent of PricewaterhouseCoopers LLP.
 
     23.2  Consent of Day Edwards Federman Propester & Christensen, P.C.
           (included in Exhibit 5.1).
 
     24.1  Power of Attorney (contained on signature page hereto).


ITEM 9.  UNDERTAKINGS.

(1)  The undersigned Registrant hereby undertakes:

     (a)  To file, during any period in which offers or sales are being made, a
          post-effective amendment to this registration statement:

          (i)    To include any prospectus required by section 10(a)(3) of the
                 Securities Act;

          (ii)   To reflect in the prospectus any facts or events arising after
                 the effective date of the registration statement (or the most
                 recent post-effective amendment thereof)


<PAGE>
 
                 which, individually or in the aggregate, represent a
                 fundamental change in the information set forth in the
                 registration statement. Notwithstanding the foregoing, any
                 increase or decrease in volume of securities offered (if the
                 total dollar value of securities offered would not exceed that
                 which was registered) and any deviation from the low or high
                 and of the estimated maximum offering range may be reflected in
                 the form of prospectus filed with the Commission pursuant to
                 Rule 424(b) if, in the aggregate, the changes in volume and
                 price represent no more than a 20 percent change in the maximum
                 aggregate offering price set forth in the "Calculation of
                 Registration Fee" table in the effective registration
                 statement;

          (iii)  To include any material information with respect to the plan of
                 distribution not previously disclosed in the registration
                 statement or any material change to such information in the
                 registration statement;

          provided, however, that paragraphs (1)(a)(i) and (1)(a)(ii) do not
          apply if the information required to be included in a post-effective
          amendment by those paragraphs is contained in periodic reports filed
          by the Registrant pursuant to Section 13 or Section 15(d) of the
          Exchange Act that are incorporated by reference in this registration
          statement.

     (b)  That, for the purpose of determining any liability under the
          Securities Act, each such post-effective amendment shall be deemed to
          be a new registration statement relating to the securities offered
          therein, and the offering of such securities at that time shall be
          deemed to be the initial bona fide offering thereof.

     (c)  To remove from registration by means of a post-effective amendment any
          of the securities being registered which remain unsold at the
          termination of the offering.

(2)  The  undersigned Registrant hereby undertakes that, for purposes of
     determining any liability  under the Securities Act, each filing of the
     Registrant's annual report pursuant to Section 13(a) or Section 15(d) of
     the Exchange Act that is incorporated by reference in the Registration
     Statement shall be deemed to be a new registration statement relating to
     the securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.

(3)  Insofar as indemnification for liabilities arising under the Securities Act
     may be permitted to directors, officers and controlling persons of the
     Registrant pursuant to the foregoing provisions, or otherwise, the
     Registrant has been advised that in the opinion of the Securities and
     Exchange Commission such indemnification is against public policy as
     expressed in the Act and is, therefore, unenforceable.  In the event that a
     claim for indemnification against such liabilities (other than the payment
     by the Registrant of expenses incurred or paid by a director, officer or
     controlling person of the Registrant in the successful defense of any
     action, suit or proceeding) is asserted by such director, officer or
     controlling person in connection with the securities being registered, the
     Registrant will, unless in the opinion of its counsel the matter has been
     settled by controlling precedent, submit to a court of appropriate
     jurisdiction the question whether such indemnification by it is against
     public policy as expressed in the Act and will be governed by the final
     adjudication of such issue.

                                     II-5
<PAGE>
 
                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, BancFirst
Corporation certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Oklahoma City, and State of Oklahoma, on the
29th day of September, 1998.

                              BANCFIRST CORPORATION


                              By: /s/  David E. Rainbolt
                                 -------------------------------------------
                                       David E. Rainbolt
                                       President and Chief Executive Officer

                               POWER OF ATTORNEY

     The officers and directors of BancFirst Corporation whose signature appears
below, hereby constitute and appoint David E. Rainbolt, Joe T. Shockley, Jr. and
Randy P. Foraker, and each of them (with full power to each of them to act
alone), the true and lawful attorney-in-fact to sign and execute, on behalf of
the undersigned, any amendment(s) to this registration statement, and each of
the undersigned does hereby ratify and confirm all that said attorneys shall do
or cause to be done by virtue thereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>
 
                Name                                   TITLE                                  DATE
                ----                                   -----                                  ----
<S>                                    <C>                                    <C>
 
/s/ H. E. Rainbolt                     Chairman of the Board                  September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
H. E. Rainbolt                        
 
 
/s/ David E. Rainbolt                  President, Chief Executive             September 29, 1998
- -------------------------------------  Officer and Director         
David E. Rainbolt                      (Principal Executive Officer) 
                                       
 
 
/s/ Joe T. Shockley, Jr.               Executive Vice President, Chief        September 29, 1998
- -------------------------------------  Financial Officer and Director 
Joe T. Shockley, Jr.                   (Principal Financial Officer)   
                                       
 
 
/s/ J. Ralph McCalmont                 Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
J. Ralph McCalmont                    
 
 
/s/ Robert A. Gregory                  Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
Robert A. Gregory                     
 
 
/s/ William O. Johnstone               Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer)
William O. Johnstone
 
/s/ K. Gordon Greer                    Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
K. Gordon Greer                       
 
 
/s/ Marion C. Bauman                   Director                               September 29, 1998
- -------------------------------------
Marion C. Bauman
 
/s/ Randy P. Foraker                   Senior Vice President, Controller      September 29, 1998
- -------------------------------------  and Secretary/Treasurer       
Randy P. Foraker                       (Principal Accounting Officer) 
</TABLE>

                                     II-6
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 22580}]
{"company-data": {"conformed-name": "BANCFIRST CORP /OK/", "cik": "0000760498", "assigned-sic": "6021", "irs-number": "731221379", "state-of-incorporation": "OK", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "file-number": "333-65129", "film-number": "98718970"}, "business-address": {"street1": "101 N BROADWAY STE 200", "street2": "D", "city": "OKLAHOMA CITY", "state": "OK", "zip": "73102-8401", "phone": "4052701000"}, "mail-address": {"street1": "101 NORTH BROADWAY", "street2": "STE 200", "city": "OKLAHOMA CITY", "state": "OK", "zip": "73102-8401"}, "former-company": {"former-conformed-name": "UNITED COMMUNITY CORP", "date-changed": "19890401"}}
As filed with the Securities and Exchange Commission on September 30, 1998
                                                           REGISTRATION NO. 333-
================================================================================
                                        
                       SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549

                                    FORM S-8

            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                             BANCFIRST CORPORATION
             (Exact name of Registrant as specified in its charter)

                                    OKLAHOMA
         (State or other jurisdiction of incorporation or organization)

          6022                                                   73-1221379
(Primary Standard Industrial                                  (I.R.S. Employer
 Classification Code Number)                                 Identification No.)

                         101 North Broadway, Suite 200
                         Oklahoma City, Oklahoma 73102
                                 (405) 270-1086
  (Address, including zip code, and telephone number, including area code, of
                   Registrants' principal executive offices)

           1988 Incentive Stock Option Plan of Security Corporation
                      as assumed by BancFirst Corporation
 
           1993 Incentive Stock Option Plan of Security Corporation
                      as assumed by BancFirst Corporation
 
       1995 Non-Employee Director Stock Plan of AmQuest Financial Corp.
                      as assumed by BancFirst Corporation
                          (Full titles of the plans)
 
                               David E. Rainbolt
                     President and Chief Executive Officer
                             BancFirst Corporation
                         101 North Broadway, Suite 200
                         Oklahoma City, Oklahoma 73102
                                (405) 270-1086
          (Name, address, including zip code, and telephone number, 
                  including area code, of agents for service)

 
                                  COPIES TO:
                           JEANETTE C. TIMMONS, ESQ.
              Day Edwards Federman Propester & Christensen, P.C.
                              2900 Oklahoma Tower
                                210 Park Avenue
                         Oklahoma City, Oklahoma 73102
                                (405) 239-2121

                        CALCULATION OF REGISTRATION FEE
====================================================================================================================================

    TITLE OF EACH CLASS OF              AMOUNT TO BE        PROPOSED MAXIMUM         PROPOSED MAXIMUM AGGREGATE     AMOUNT OF
 SECURITIES TO BE REGISTERED            REGISTERED (1)  OFFERING PRICE PER SHARE (2)     OFFERING PRICE (2)     REGISTRATION FEE (3)

- ------------------------------------------------------------------------------------------------------------------------------------
Common Stock, $0.01 par value per share    116,461               $37.75                       $4,396,403              $1,297
====================================================================================================================================
(1)  Pursuant to Rule 416(a), also covers additional securities that may be
     offered as a result of stock splits, stock dividends or similar
     transactions.
(2)  Estimated solely for the purpose of determining the registration fee and
     calculated pursuant to Rule 457(c) based upon the average of the high and
     low prices of the Common Stock on the Nasdaq National Market on September
     29, 1998, which was $37.75.
(3)  The registration fee was calculated pursuant to Rule 457(c), as $295 per $1
     million.
INTRODUCTION

     This Registration Statement on Form S-8 is filed by BancFirst Corporation,
an Oklahoma corporation (the "Company," BancFirst or the "Registrant"), relating
to an aggregate 116,461 shares of its common stock, par value $1.00 per share
(the "Common Stock") issuable under the 1988 Incentive Stock Option Plan of
Security Corporation, the 1993 Incentive Stock Option Plan of Security
Corporation and the 1995 Non-Employee Director Stock Option Plan of AmQuest
Financial Corp., all of which have been assumed by BancFirst pursuant to the
Merger Agreement dated May 6, 1998 between BancFirst and AmQuest Financial Corp.
(collectively, the "Plans").

                                     PART I
                                        
                INFORMATION REQUIRED IN SECTION 10(a) PROSPECTUS
                                        
ITEM 1.  PLAN INFORMATION.

     Not filed as part of this Registration Statement pursuant to Note to Part 1
of Form S-8.

ITEM 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.

     Not filed as part of this Registration Statement pursuant to Note to Part 1
of Form S-8.

                                    PART II
                                        
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
                                        
ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents, which previously have been filed by the Company
with the Securities and Exchange Commission (the "Commission"), are incorporated
herein by reference and made a part hereof:

     (i)    The Company's latest Annual Report on Form 10-K for the fiscal year
            ended December 31, 1997;

     (ii)   All other reports filed pursuant to Section 13(a) or 15(d) of the
            Securities Exchange Act of 1934 (the "Exchange Act") since the end
            of the fiscal year covered by the Annual Report referred to in (i)
            above; and

     (iii)  The description of the Company's Common Stock contained in the
            Company's Registration Statement on Form 8A/A (Registration No. 
            000-14384), filed with the Commission on July 24, 1998, including
            any amendment or reports filed for the purpose of updating such
            description.

     All reports and other documents filed by the Company pursuant to Sections
13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of this
Registration Statement and prior to the filing of a post-effective amendment
hereto, which indicates that all securities offered hereunder have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference herein and to be a part hereof from the date of filing
of such documents.

     For purposes of this Registration Statement, any document or any statement
contained in a document incorporated or deemed to be incorporated herein by
reference shall be deemed to be modified or superseded to the extent that a
subsequently filed document or a statement contained herein or in any other
subsequently filed document which also is or is deemed to be incorporated herein
by reference modifies or supersedes such document or such statement in such
document.  Any statement so modified or superseded shall not be deemed, except
as so modified or superseded, to constitute a part of this Registration
Statement.

                                     II-2
ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 1006(B)(7) of the General Corporation Act of the State of Oklahoma
(the "OGCA") authorizes a corporation in its certificate of incorporation to
eliminate or limit the personal liability of members of its board of directors
to the corporation or its stockholders for monetary damages for violations of a
director's fiduciary duty of care, including acts constituting gross negligence.
Such a provision would have no effect on the availability of equitable remedies,
such as an injunction or rescission, for breach of fiduciary duty.  In addition,
no such provision may eliminate or limit the liability of a director for
breaching his duty of loyalty to the corporation or its shareholders, failing to
act in good faith, engaging in intentional misconduct or knowingly violating a
law, paying an unlawful dividend or approving an illegal stock repurchase, or
executing any transaction from which the director obtained an improper personal
benefit.

     Section 1031 of the OGCA empowers a corporation to indemnify any person who
was or is a party to or is threatened to be made a party to any threatened,
pending or completed action, suit or proceeding, whether civil, criminal,
administrative or investigative (other than an action by or in the right of the
corporation), by reason of the fact that he is or was a director, officer,
employee or agent of the corporation, or is or was serving at the request of the
corporation as a director, officer, employee or agent of another corporation,
partnership, joint venture, trust or other enterprise, against expenses
(including attorney's fees), judgments, fines and amounts paid in settlement
actually and reasonably incurred by him in connection with such action, suit or
proceeding if he acted in good faith and in a manner he reasonably believed to
be in or not opposed to the best interests of the corporation, and, with respect
to any criminal action or proceeding, had no reasonable cause to believe his
conduct was unlawful.  With respect to actions or suits by or in the right of
the corporation, such indemnification is limited to expenses (including
attorneys' fees) actually and reasonably incurred by such person in connection
with the defense or settlement of such action or suit.  Further, no
indemnification shall be made in respect of any claim, issue or matter as to
which such person shall have been adjudged to be liable to the corporation
unless and only to the extent that the court in which such action or suit was
brought shall determine upon application that, despite the adjudication of
liability but in view of all the circumstances of the case, such person is
fairly and reasonably entitled to indemnity for such expenses which the court
shall deem proper.  Additionally, a corporation is required to indemnify its
directors and officers against expenses to the extent that such directors or
officers have been successful on the merits or otherwise in defense of any
action, suit or proceeding referred to above or in defense of any claim, issue
or matter therein.

     An indemnification can be made by the corporation only upon a determination
made in the manner prescribed by the statute that indemnification is proper in
the circumstances because the party seeking indemnification has met the
applicable standard of conduct as set forth in the OGCA.  The indemnification
provided by the OGCA shall not be deemed exclusive of any other rights to which
those seeking indemnification may be entitled under any bylaw, agreement, vote
of stockholders or disinterested directors, or otherwise.  A corporation also
has the power to purchase and maintain insurance on behalf of any person
covering any liability incurred by such person in his capacity as a director,
officer, employee or agent of the corporation, or arising out of his status as
such, whether or not the corporation would have the power to indemnify him
against such liability.  The indemnification provided by the OGCA shall, unless
otherwise provided when authorized or ratified, continue as to a person who has
ceased to be a director, officer, employee or agent and shall inure to the
benefit of the heirs, executors and administrators of such a person.

                                     II-3
THE COMPANY'S CHARTER AND BYLAW PROVISIONS

     The Company's Amended and Restated Certificate of Incorporation (i) limits
its directors' liability for monetary damages to the Company and its
shareholders for breach of fiduciary duty except under the circumstances
outlined in Section 1006(B)(7) of the OGCA as described above, (ii) provides for
elimination or limitation of liability to the fullest extent permitted should
the OGCA be amended to authorize corporation action further eliminating or
limiting the personal liability of directors and (iii) provides for
indemnification to the fullest extent permitted by Section 1031 of the OGCA.

OTHER ARRANGEMENTS

     The Company maintains a directors' and officers' liability insurance policy
insuring its directors and officers against certain liabilities and expenses
incurred by them in their capacities as such and insuring the Company, under
certain circumstances, in the event that indemnification payments are made by
the Company to such directors and officers.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

Not applicable.

ITEM 8.  EXHIBITS.

     Unless otherwise indicated below as being incorporated by reference to
another filing of the Company with the Commission, each of the following
exhibits is filed herewith:

  Exhibit
   Number                           Name of Exhibit
   ------                           ---------------
 
      4.1  1988 Incentive Stock Option Plan of Security Corporation as assumed
           by BancFirst Corporation.
 
      4.2  1993 Incentive Stock Option Plan of Security Corporation as assumed
           by BancFirst Corporation.
 
      4.3  1995 Non-Employee Director Stock Plan of AmQuest Financial Corp. as
           assumed by BancFirst Corporation.
 
      5.1  Opinion of Day, Edwards, Federman, Propester & Christensen, P.C. as
           to the legality of the BancFirst Common Stock.
 
     23.1  Consent of PricewaterhouseCoopers LLP.
 
     23.2  Consent of Day Edwards Federman Propester & Christensen, P.C.
           (included in Exhibit 5.1).
 
     24.1  Power of Attorney (contained on signature page hereto).

ITEM 9.  UNDERTAKINGS.

(1)  The undersigned Registrant hereby undertakes:

     (a)  To file, during any period in which offers or sales are being made, a
          post-effective amendment to this registration statement:

          (i)    To include any prospectus required by section 10(a)(3) of the
                 Securities Act;

          (ii)   To reflect in the prospectus any facts or events arising after
                 the effective date of the registration statement (or the most
                 recent post-effective amendment thereof)
which, individually or in the aggregate, represent a
                 fundamental change in the information set forth in the
                 registration statement. Notwithstanding the foregoing, any
                 increase or decrease in volume of securities offered (if the
                 total dollar value of securities offered would not exceed that
                 which was registered) and any deviation from the low or high
                 and of the estimated maximum offering range may be reflected in
                 the form of prospectus filed with the Commission pursuant to
                 Rule 424(b) if, in the aggregate, the changes in volume and
                 price represent no more than a 20 percent change in the maximum
                 aggregate offering price set forth in the "Calculation of
                 Registration Fee" table in the effective registration
                 statement;

          (iii)  To include any material information with respect to the plan of
                 distribution not previously disclosed in the registration
                 statement or any material change to such information in the
                 registration statement;

          provided, however, that paragraphs (1)(a)(i) and (1)(a)(ii) do not
          apply if the information required to be included in a post-effective
          amendment by those paragraphs is contained in periodic reports filed
          by the Registrant pursuant to Section 13 or Section 15(d) of the
          Exchange Act that are incorporated by reference in this registration
          statement.

     (b)  That, for the purpose of determining any liability under the
          Securities Act, each such post-effective amendment shall be deemed to
          be a new registration statement relating to the securities offered
          therein, and the offering of such securities at that time shall be
          deemed to be the initial bona fide offering thereof.

     (c)  To remove from registration by means of a post-effective amendment any
          of the securities being registered which remain unsold at the
          termination of the offering.

(2)  The  undersigned Registrant hereby undertakes that, for purposes of
     determining any liability  under the Securities Act, each filing of the
     Registrant's annual report pursuant to Section 13(a) or Section 15(d) of
     the Exchange Act that is incorporated by reference in the Registration
     Statement shall be deemed to be a new registration statement relating to
     the securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.

(3)  Insofar as indemnification for liabilities arising under the Securities Act
     may be permitted to directors, officers and controlling persons of the
     Registrant pursuant to the foregoing provisions, or otherwise, the
     Registrant has been advised that in the opinion of the Securities and
     Exchange Commission such indemnification is against public policy as
     expressed in the Act and is, therefore, unenforceable.  In the event that a
     claim for indemnification against such liabilities (other than the payment
     by the Registrant of expenses incurred or paid by a director, officer or
     controlling person of the Registrant in the successful defense of any
     action, suit or proceeding) is asserted by such director, officer or
     controlling person in connection with the securities being registered, the
     Registrant will, unless in the opinion of its counsel the matter has been
     settled by controlling precedent, submit to a court of appropriate
     jurisdiction the question whether such indemnification by it is against
     public policy as expressed in the Act and will be governed by the final
     adjudication of such issue.

                                     II-5
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, BancFirst
Corporation certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Oklahoma City, and State of Oklahoma, on the
29th day of September, 1998.

                              BANCFIRST CORPORATION

                              By: /s/  David E. Rainbolt
                                 -------------------------------------------
                                       David E. Rainbolt
                                       President and Chief Executive Officer

                               POWER OF ATTORNEY

     The officers and directors of BancFirst Corporation whose signature appears
below, hereby constitute and appoint David E. Rainbolt, Joe T. Shockley, Jr. and
Randy P. Foraker, and each of them (with full power to each of them to act
alone), the true and lawful attorney-in-fact to sign and execute, on behalf of
the undersigned, any amendment(s) to this registration statement, and each of
the undersigned does hereby ratify and confirm all that said attorneys shall do
or cause to be done by virtue thereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
Name                                   TITLE                                  DATE
                ----                                   -----                                  ----
/s/ H. E. Rainbolt                     Chairman of the Board                  September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
H. E. Rainbolt                        
 
 
/s/ David E. Rainbolt                  President, Chief Executive             September 29, 1998
- -------------------------------------  Officer and Director         
David E. Rainbolt                      (Principal Executive Officer) 
                                       
 
 
/s/ Joe T. Shockley, Jr.               Executive Vice President, Chief        September 29, 1998
- -------------------------------------  Financial Officer and Director 
Joe T. Shockley, Jr.                   (Principal Financial Officer)   
                                       
 
 
/s/ J. Ralph McCalmont                 Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
J. Ralph McCalmont                    
 
 
/s/ Robert A. Gregory                  Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
Robert A. Gregory                     
 
 
/s/ William O. Johnstone               Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer)
William O. Johnstone
 
/s/ K. Gordon Greer                    Vice Chairman of the Board             September 29, 1998
- -------------------------------------  (Principal Executive Officer) 
K. Gordon Greer                       
 
 
/s/ Marion C. Bauman                   Director                               September 29, 1998
- -------------------------------------
Marion C. Bauman
 
/s/ Randy P. Foraker                   Senior Vice President, Controller      September 29, 1998
- -------------------------------------  and Secretary/Treasurer       
Randy P. Foraker                       (Principal Accounting Officer)
II-6