As filed with the Securities and Exchange Commission on March 17, 2005
                                                   Registration No. 333-______

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                       FIRST HORIZON NATIONAL CORPORATION
             (Exact name of registrant as specified in its charter)

         TENNESSEE                                        62-0803242
(State or other jurisdiction of                       (I.R.S. Employer
 incorporation or organization)                       Identification No.)

                               165 Madison Avenue
                            Memphis, Tennessee 38103
                                 (901) 523-4444
              (Address, including zip code, and telephone number,
        including area code, of registrant's principal executive offices)

        First Horizon National Corporation 2003 Equity Compensation Plan
                              (Full title of plan)

Harry A. Johnson, III                      With a copy to:
Executive Vice President and
    General Counsel                        Clyde A.  Billings, Jr.
First Horizon National Corporation         Senior Vice President, Assistant
165 Madison Avenue                         General Counsel and
Memphis, Tennessee  38103                  Corporate Secretary
(901) 523-5624                             First Horizon National Corporation
(Name, address, including zip code,        165 Madison Avenue
 and telephone number, including area      Memphis, TN  38103
 code, of agent for service)               (901) 523-5679


                         CALCULATION OF REGISTRATION FEE
================================================================================
Title of    Amount to be   Proposed Maxi-   Proposed Maxi-  Amount of
Securities  Registered     mum Offering     mum Aggregate   Registration
To be                      Price per        Offering        Fee (1)
Registered                 Share (1)        Price (1)
----------  ------------   --------------   --------------  -------------
Common      1,000,000      $42.72           $42,720,000     $5,028.15
Stock*      shares
================================================================================
* Including related Rights

(1) Estimated and calculated pursuant to Rule 457(h)(1), based on the average of
    the high and low prices  reported on the New York Stock  Exchange  composite
    tape for Registrant's stock on March 14, 2005.



Note on Filing History

     On October 21, 2003,  First  Horizon  National  Corporation  ("FHNC" or the
"Registrant") filed a registration  statement on Form S-8 (File No. 333-109862),
registering  3,000,000  shares of its common stock,  par value $0.625 per share,
for sale under  Registrant's 2003 Equity  Compensation Plan (as amended to date,
the  "Plan").  Registrant  is filing  this  registration  statement  to register
1,000,000  additional  shares of  Registrant's  common  stock for sale under the
Plan, which was amended February 17, 2004 (approved by the shareholders on April
20, 2004) to increase by 1,000,000 the number of shares authorized for issuance.


                                     PART I

     The Section  10(a)  prospectus  relating  to the Plan is omitted  from this
Registration Statement pursuant to the Note to Part I of Form S-8.


                                     PART II

                 INFORMATION REQUIRED IN REGISTRATION STATEMENT

     As permitted  by  Instruction  E to Form S-8, the contents of  Registrant's
registration  statement  on Form S-8  (File  No.  333-109862),  which  was filed
October 21, 2003, covering shares for sale under the Plan, as updated below, are
incorporated  herein by reference.  In addition to the foregoing,  the following
information is also included in this registration statement:

Item 5.  Interests of Named Experts and Counsel

     KPMG LLP, the Registrant's independent accountants, have no interest in the
Registrant.

     The  validity of original  issue shares of $0.625 par value common stock of
First Horizon  National  Corporation  ("FHNC" or the  "Registrant") to be issued
pursuant to the Plan has been passed upon by Clyde A. Billings, Jr., Senior Vice
President,  Assistant General Counsel and Corporate  Secretary of FHNC. On March
1, 2005,  the number of shares,  including  options,  beneficially  owned by Mr.
Billings was approximately 47,934 shares.

Item 6.  Indemnification of Directors and Officers

     Tennessee Code Annotated Sections  48-18-501 through 48-18-509  authorize a
corporation to provide for the indemnification of officers, directors, employees
and agents in terms sufficiently broad to permit  indemnification  under certain
circumstances for liabilities  (including  reimbursement for expenses  incurred)
arising  under the  Securities  Act of 1933,  as  amended.  FHNC has adopted the
provisions of the Tennessee  statute  pursuant to Article Six of its Bylaws.  In
addition,  FHNC has a directors' and officers'  liability insurance policy which
provides coverage  sufficiently  broad to permit  indemnification  under certain
circumstances for liabilities  (including  reimbursement for expenses  incurred)
arising under the Securities Act of 1933, as amended.

                                       2



     Tennessee Code Annotated,  Section 48-12-102,  permits the inclusion in the
charter of a Tennessee  corporation  of a provision,  with  certain  exceptions,
eliminating the personal  monetary  liability of directors to the corporation or
its shareholders for breach of the duty of care. FHNC has adopted the provisions
of the statute as Article 13 of its charter.

     The  shareholders  of FHNC have approved an amendment to Article Six of the
Bylaws  pursuant to which FHNC is required to  indemnify  each  director and any
officers  designated by the Board of  Directors,  and advance  expenses,  to the
maximum  extent not  prohibited by law. In accordance  with the  foregoing,  the
Board of Directors is authorized to enter into individual  indemnity  agreements
with the  directors  and such  officers.  Such  indemnity  agreements  have been
approved for all of the directors and certain officers.

Item 8.  Exhibits

All Exhibits are listed in the Exhibit Index at the end of this Part II.

Item 9.  Undertakings

(a) The undersigned registrant hereby undertakes:

    (1) 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 of 1933;

       (ii) To reflect in the  prospectus  any fact 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,  represents a fundamental  change in the  information set
            forth in the 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 (a)(1)(i) and (a)(1)(ii) do not apply
        if the  registration  statement  is on  Form  S-3 or Form  S-8,  and 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  Securities
        Exchange  Act  of  1934  that  are  incorporated  by  reference  in  the
        registration statement.

    (2) That, for the purpose of determining  any liability under the Securities
        Act of 1933, 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.

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    (3) 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.

(b) The  undersigned   registrant   hereby  undertakes  that,  for  purposes  of
    determining  any liability  under the Securities Act of 1933, each filing of
    the registrant's annual report pursuant to Section 13(a) or Section 15(d) of
    the Securities Exchange Act of 1934, (and, where applicable,  each filing of
    an employee  benefit  plan's annual report  pursuant to Section 15(d) of the
    Securities  Exchange Act of 1934) 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.

(c) Insofar as indemnification  for liabilities arising under the Securities Act
    of 1933 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.


                                       4


                                   SIGNATURES
                                   ----------

The Registrant.  Pursuant to the requirements of the Securities Act of 1933, the
registrant 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 Memphis and State of Tennessee, on March 17, 2005.

FIRST HORIZON NATIONAL CORPORATION


By: /s/Marlin L. Mosby, III
    -------------------------
       Marlin L. Mosby, III
       Executive Vice President and
       Chief Financial Officer


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
date indicated.

Signature                 Title                         Date
----------------------    ---------------------         --------------

J.  Kenneth  Glass*       Chairman  of the Board,       March 17,  2005 
J.  Kenneth  Glass        President, Chief Executive
                          Officer and a Director
                         (principal executive officer)

Marlin L. Mosby, III*     Executive Vice President      March 17, 2005
Marlin L. Mosby, III      and Chief Financial Officer
                         (principal financial officer)

James F. Keen*            Executive Vice President      March 17, 2005
James F. Keen             and Corporate Controller
                         (principal accounting officer)

Robert C. Blattberg*      Director                      March 17, 2005
Robert C. Blattberg

George E. Cates*          Director                      March 17, 2005
George E. Cates

Simon F. Cooper*          Director                      March 17, 2005
Simon F. Cooper

James A. Haslam, III*     Director                      March 17, 2005
James A. Haslam, III

R. Brad Martin*           Director                      March 17, 2005
R. Brad Martin


                                       5


Vicki R. Palmer*          Director                      March 17, 2005
Vicki R. Palmer

Michael D. Rose*          Director                      March 17, 2005
Michael D. Rose

Mary F. Sammons*          Director                      March 17, 2005
Mary F. Sammons

William B. Sansom*        Director                      March 17, 2005
William B. Sansom

Jonathan P. Ward*         Director                      March 17, 2005
Jonathan P. Ward

Luke Yancy III*           Director                      March 17, 2005
Luke Yancy III



*By: /s/ Clyde A. Billings, Jr.
    ---------------------------
         Clyde A. Billings, Jr.
         Attorney-in-Fact
         March 17, 2005


                                       6



                                  EXHIBIT INDEX
                                  -------------


Exhibit 4.1

Amended  and  Restated  Charter  of  the  Corporation,  incorporated  herein  by
reference to Exhibit 3(i) to the Corporation's Quarterly Report on Form 10-Q for
the quarter ended 3-31-04.

Exhibit 4.2

Bylaws of the Corporation,  as amended and restated as of 1-18-05,  incorporated
herein by reference to Exhibit 3.2 to the  Corporation's  Annual  Report on Form
10-K for the year ended December 31, 2004.

Exhibit 4.3

Shareholder  Protection Rights Agreement,  dated as of October 20, 1998, between
the Corporation and First Tennessee Bank National Association,  as Rights Agent,
including as Exhibit A the forms of Rights  Certificate and Election to Exercise
and as Exhibit B the form of Articles  of  Amendment  designating  Participating
Preferred Stock, incorporated herein by reference to Exhibits 1, 2, and 3 to the
Corporation's Registration Statement on Form 8-A filed 10-23-98.

Exhibit 5.1

Opinion and consent of Clyde A. Billings, Jr. concerning the legality
of the securities being registered hereunder.

Exhibit 23.1

Consent of Independent Accountants.

Exhibit 24.1

Power of Attorney executed by certain directors and officers of the Registrant.


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