UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                        POST EFFECTIVE AMENDMENT NO. 1 TO
                                    FORM S-8
                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                              TRUSTMARK CORPORATION
              (Exact name of registrant as specified in it charter)


        Mississippi                                                64-0471500
(State or other jurisdiction of                                 (I.R.S. Employer
incorporation or organization)                               Identification No.)


                   248 East Capitol Street, Jackson, MS 39201
           (Address of principal executive offices including zip code)


                              Trustmark 401(k) Plan
          (as Successor to Trustmark National Bank Profit Sharing Plan)
                            (Full title of the plan)


                                 LOUIS E. GREER
                            Chief Accounting Officer
                              Trustmark Corporation
                              248 E. Capitol Street
                                Jackson, MS 39201
                       (601) 208-2310, Fax (601) 208-6871
                   (Name and address, including area code and
                     telephone number, of agent for service)


                        Copies of all correspondence to:
                              Robert D. Drinkwater
                     Brunini, Grantham, Grower & Hewes, PLLC
                             Post Office Drawer 119
                                Jackson, MS 39205
                       (601) 948-3101, Fax (601) 960-6902

<PAGE>

CALCULATION OF REGISTRATION FEE

                                   Proposed        Proposed
Title of                           maximum         maximum
securities        Amount           offering        aggregate         Amount of
to be             to be            price           offering          registra-
registered        registered       per share       price              tion fee
----------        ----------       ---------       -----------       ---------
Common Stock
$0.00 par value
per share         2,500,000        $28.06          $70,150,000         $8,888

Includes an estimated number of Trustmark  Corporation  shares to be acquired in
the  near  future  by  employees  of  Trustmark   Corporation  and  subsidiaries
("Trustmark") under the Trustmark 401 (k) Plan ("the "Plan").

(1)  In addition, pursuant to Rule 416(c) under the Securities Act of 1933, this
     registration  statement also covers an indeterminate amount of interests to
     be offered pursuant to the Plan.

(2)  Registration  Fee has been  calculated in accordance with Rule 457(h) under
     the  Securities  Act of 1933 and is based upon the  average of the high and
     low prices for Trustmark's  shares reported on the NASDAQ System on October
     27, 2003.

Approximate  date of  commencement  of proposed  sale to the public:  As soon as
practicable after this Registration Statement becomes effective.

If any securities  being  registered on this form are to be offered on a delayed
or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check
the following box. [x]

<PAGE>

Explanation

     This  Post-Effective  Amendment No. 1 is being filed to register  2,500,000
additional  shares of Trustmark  Corporation  Common Stock issuable  pursuant to
Registrant's  401(k) Plan, which Plan amended  Registrant's  Profit Sharing Plan
and certain  other  employee  benefit  plans.  Registrant  initially  registered
250,000 shares pursuant to a registration statement on Form S-8 for Registrant's
Profit Sharing Plan which became  effective  July 17,1996 (File No.  333-07141).
Effective March 30, 1998, Registrant's shares were split 2 for 1, increasing the
number of registered  shares to 500,000.  Effective  January 1, 2004 the Plan is
being  further  amended and  converted to a stock bonus plan,  with a designated
portion of the Plan being an employee stock ownership plan. With this amendment,
there will be a total of 3,000,000 shares registered.

     The  contents of the earlier  Registration  Statement on Form S-8 (File No.
333- 07141) are incorporated herein by reference


Part II

Item 3.  Incorporation of Documents by Reference.

     In  addition  to  the  documents   incorporated   by  reference   into  the
Registration  Statement  on Form S-8 (File No. 333- 07141) with respect to which
this amendment is being filed, the Registrant  incorporates by reference in this
Registration  Statement all reports  previously filed with the Commission by the
Plan or subsequently  filed pursuant to Sections  13(a),  13(c), 14 and 15(d) of
the  Securities  Exchange Act of 1934,  prior to the filing of a  post-effective
amendment which  indicates that all securities  offered herein have been sold or
which deregisters all securities then remaining unsold.


Item 8.  Exhibits.

         5.       Opinion re Legality

         23.1     Consent of KPMG LLP regarding Form 11-K

         23.2     Consent of KPMG LLP regarding Form 10-K

         23.3     Consent of Brunini, Grantham Grower & Hewes, PLLC

         99.      Undertaking

<PAGE>


SIGNATURES

Pursuant to the  requirements  of the  Securities  Act of 1933, as amended,  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  Post
Effective  Amendment  to be signed on its behalf by the  undersigned,  thereunto
duly authorized, in the City of Jackson and State of Mississippi on the 27th day
of October, 2003.

                              TRUSTMARK CORPORATION


                              /s/ Richard G. Hickson
                              ----------------------
                              Richard G. Hickson
                              President and Chief Executive Officer



Pursuant to the  requirements  of the Securities  Act of 1933, as amended,  this
Post  Effective  Amendment  to  Registration  Statement  has been  signed by the
following persons in the capacities and on the date indicated.

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

/s/ Richard G. Hickson                                          October 27, 2003
----------------------
Richard G. Hickson             Chairman, President and Chief
                               Executive Officer (Principal
                               Executive Officer), Director

/s/ Zach L. Wasson             Treasurer (Principal Financial   October 27, 2003
------------------             Officer)
Zach L. Wasson

/s/ Louis E. Greer             Chief Accounting Officer         October 27, 2003
------------------
Louis E. Greer                 (Principal Accounting Officer)

/s/ J. Kelly Allgood           Director                         October 27, 2003
--------------------
J. Kelly Allgood




<PAGE>




/s/ Reuben V. Anderson         Director                         October 27, 2003
----------------------
Reuben V. Anderson

                               Director
-----------------
John L. Black, Jr.

/s/ William C. Deviney,  Jr.   Director                         October 27, 2003
----------------------------
William C. Deviney, Jr.

/s/ C. Gerald Garnett          Director                         October 27, 2003
---------------------
C. Gerald Garnett

/s/ Matthew L. Holleman III    Director                         October 27, 2003
---------------------------
 Matthew L. Holleman III

/s/ William Neville III        Director                         October 27, 2003
-----------------------
William Neville III

/s/ Richard H. Puckett         Director                         October 27, 2003
----------------------
Richard H. Puckett

/s/ Carolyn C. Shanks          Director                         October 27, 2003
---------------------
Carolyn C. Shanks

/s/ Kenneth W. Williams        Director                         October 27, 2003
------------------------
Kenneth W. Williams

/s/ William G. Yates,  Jr.     Director                         October 27, 2003
--------------------------
William G. Yates, Jr.

<PAGE>

                     BRUNINI, GRANTHAM, GROWER & HEWES, PLLC

TELEPHONE                  ATTORNEYS AT LAW                   MAILING ADDRESS
(601) 948-3101         1400 TRUSTMARK BUILDING            POST OFFICE DRAWER 119
                       248 EAST CAPITOL STREET        JACKSON, MISSISSIPPI 39205
FACSIMILE            JACKSON, MISSISSIPPI 39201
(601) 960-6902


Exhibit 5

                                October 28, 2003

The Board of Directors of
Trustmark Corporation
248 East Capitol Street
Jackson, Mississippi 39201

Ladies and Gentlemen:

     We  have  acted  as  counsel  to  Trustmark   Corporation,   a  Mississippi
corporation (the "Company") and its 401(k) Plan (the "Plan"), in connection with
a Post  Effective  Amendment  to a  Registration  Statement  on Form  S-8  (File
No.333-07141)  with respect to the  Company's  common  stock,  no par value (the
"Common  Securities") being offered pursuant to the Plan as well as interests in
the Plan.

     We have reviewed such corporate records,  certificates and other documents,
and such questions of law, as we have  considered  necessary or appropriate  for
the purposes of this  opinion.  We have assumed that each of the parties  (other
than the Company) has duly  authorized,  executed and delivered the documents to
which it is a party.

     We have relied as to certain  matters on  information  obtained from public
officials,  officers  of the  Company,  and other  sources  believed by us to be
responsible.

     Based  upon the  foregoing,  and  subject to the  qualifications  set forth
below, we are of the opinion that:

(1). The Company is a corporation  duly  incorporated,  validly  existing and in
     good standing under the laws of the State of Mississippi.

(2). When issued, such Common Securities will be validly issued,  fully paid and
     nonassessable.

     The foregoing opinion is subject to the  qualifications  that we express no
     opinion as to (i) waivers of defenses or statutory or constitutional rights
     or waivers of unmatured claims or rights,  (ii) rights to  indemnification,
     contribution  or  exculpation  to the extent that they purport to indemnify
     any party against,  or release or limit any party's  liability for, its own
     breach or failure to comply with  statutory  obligations,  or to the extent
     such  provisions  are  contrary  to  public  policy,  or  (iii)  rights  to
     collection of liquidated damages or penalties.

     We are members of the bar of the State of Mississippi. We do not purport to
     be experts  in, and do not  express any opinion on, any laws other than the
     law of the State of Mississippi and the Federal law of the United States of
     America.


                                    Very truly yours,

                                    Brunini, Grantham, Grower & Hewes, PLLC


                                    /s/ Robert D. Drinkwater
                                    ------------------------
                                    Robert D. Drinkwater

<PAGE>

Exhibit 23.1

                          Independent Auditors' Consent



The Board of Directors
Trustmark Corporation:

We  consent to the use of our report  dated  June 6, 2003,  with  respect to the
financial  statements and supplemental  schedule of Trustmark 401 (k) Plan as of
December 31, 2002 and 2001,  and for the year ended  December  31,  2002,  which
report  appears in the December 31, 2002 annual report on Form 11-K of Trustmark
401 (k) Plan, incorporated by reference herein.


                                  /s/ KPMG LLP
                                  ------------
Jackson, Mississippi
October 27, 2003

<PAGE>

Exhibit 23.2

                          Independent Auditors' Consent



The Board of Directors
Trustmark Corporation:

We consent to the use of our report dated January 20, 2003,  with respect to the
consolidated balance sheets of Trustmark Corporation as of December 31, 2002 and
2001,   and  the  related   consolidated   statements  of  income,   changes  in
shareholders'  equity  and cash  flows for each of the  years in the  three-year
period ended  December 31, 2002,  which report  appears in the December 31, 2002
annual report on Form 10-K of Trustmark  Corporation,  incorporated by reference
herein.  Our report refers to changes in the method of accounting for derivative
instruments, hedging activities, goodwill and other intangible assets.


                                  /s/ KPMG LLP
                                  ------------
Jackson, Mississippi
October 27, 2003

<PAGE>

Exhibit 23.3



               CONSENT OF BRUNINI, GRANTHAM, GROWER & HEWES, PLLC

We hereby  consent to the inclusion of our opinion in Post  Effective  Amendment
No. 1 to the Registration Statement  (Registration Number 333-07141) on Form S-8
of Trustmark Corporation filed on or about October 29, 2003 and to the filing of
our legal (Exhibit 5) opinion as an Exhibit to such Registration Statement.

                                  BRUNINI, GRANTHAM, GROWER & HEWES, PLLC

                                  /s/ Robert D. Drinkwater
                                  ------------------------
                                  Robert D. Drinkwater

Jackson, Mississippi
October 28, 2003

<PAGE>

Exhibit 99.1

Registrant  undertakes  that it will  submit or has  submitted  the Plan and any
amendments  thereto to the Internal  Revenue  Service ("IRS") in a timely manner
and has made or will make all  changes  required  by the IRS in order to qualify
the Plan.
[{"type": "S-8", "sequence": "1", "filename": "s8_102803.txt", "description": "S-8 FILED 10/29/03", "secsgml_size_bytes": 13974}]
{"company-data": {"conformed-name": "TRUSTMARK CORP", "cik": "0000036146", "assigned-sic": "6021", "irs-number": "640471500", "state-of-incorporation": "MS", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-110066", "film-number": "03963906"}, "business-address": {"street1": "248 E CAPITOL ST", "street2": "P O BOX 291", "city": "JACKSON", "state": "MS", "zip": "39201", "phone": "6013545111"}, "mail-address": {"street1": "248 EAST CAPITOL STREET", "city": "JACKSON", "state": "MS", "zip": "39201"}, "former-company": {"former-conformed-name": "FIRST CAPITAL CORP", "date-changed": "19900513"}}
UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                        POST EFFECTIVE AMENDMENT NO. 1 TO
                                    FORM S-8
                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                              TRUSTMARK CORPORATION
              (Exact name of registrant as specified in it charter)

        Mississippi                                                64-0471500
(State or other jurisdiction of                                 (I.R.S. Employer
incorporation or organization)                               Identification No.)

                   248 East Capitol Street, Jackson, MS 39201
           (Address of principal executive offices including zip code)

                              Trustmark 401(k) Plan
          (as Successor to Trustmark National Bank Profit Sharing Plan)
                            (Full title of the plan)

                                 LOUIS E. GREER
                            Chief Accounting Officer
                              Trustmark Corporation
                              248 E. Capitol Street
                                Jackson, MS 39201
                       (601) 208-2310, Fax (601) 208-6871
                   (Name and address, including area code and
                     telephone number, of agent for service)

                        Copies of all correspondence to:
                              Robert D. Drinkwater
                     Brunini, Grantham, Grower & Hewes, PLLC
                             Post Office Drawer 119
                                Jackson, MS 39205
                       (601) 948-3101, Fax (601) 960-6902
CALCULATION OF REGISTRATION FEE

                                   Proposed        Proposed
Title of                           maximum         maximum
securities        Amount           offering        aggregate         Amount of
to be             to be            price           offering          registra-
registered        registered       per share       price              tion fee
----------        ----------       ---------       -----------       ---------
Common Stock
$0.00 par value
per share         2,500,000        $28.06          $70,150,000         $8,888

Includes an estimated number of Trustmark  Corporation  shares to be acquired in
the  near  future  by  employees  of  Trustmark   Corporation  and  subsidiaries
("Trustmark") under the Trustmark 401 (k) Plan ("the "Plan").

(1)  In addition, pursuant to Rule 416(c) under the Securities Act of 1933, this
     registration  statement also covers an indeterminate amount of interests to
     be offered pursuant to the Plan.

(2)  Registration  Fee has been  calculated in accordance with Rule 457(h) under
     the  Securities  Act of 1933 and is based upon the  average of the high and
     low prices for Trustmark's  shares reported on the NASDAQ System on October
     27, 2003.

Approximate  date of  commencement  of proposed  sale to the public:  As soon as
practicable after this Registration Statement becomes effective.

If any securities  being  registered on this form are to be offered on a delayed
or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check
the following box. [x]
Explanation

     This  Post-Effective  Amendment No. 1 is being filed to register  2,500,000
additional  shares of Trustmark  Corporation  Common Stock issuable  pursuant to
Registrant's  401(k) Plan, which Plan amended  Registrant's  Profit Sharing Plan
and certain  other  employee  benefit  plans.  Registrant  initially  registered
250,000 shares pursuant to a registration statement on Form S-8 for Registrant's
Profit Sharing Plan which became  effective  July 17,1996 (File No.  333-07141).
Effective March 30, 1998, Registrant's shares were split 2 for 1, increasing the
number of registered  shares to 500,000.  Effective  January 1, 2004 the Plan is
being  further  amended and  converted to a stock bonus plan,  with a designated
portion of the Plan being an employee stock ownership plan. With this amendment,
there will be a total of 3,000,000 shares registered.

     The  contents of the earlier  Registration  Statement on Form S-8 (File No.
333- 07141) are incorporated herein by reference

Part II

Item 3.  Incorporation of Documents by Reference.

     In  addition  to  the  documents   incorporated   by  reference   into  the
Registration  Statement  on Form S-8 (File No. 333- 07141) with respect to which
this amendment is being filed, the Registrant  incorporates by reference in this
Registration  Statement all reports  previously filed with the Commission by the
Plan or subsequently  filed pursuant to Sections  13(a),  13(c), 14 and 15(d) of
the  Securities  Exchange Act of 1934,  prior to the filing of a  post-effective
amendment which  indicates that all securities  offered herein have been sold or
which deregisters all securities then remaining unsold.

Item 8.  Exhibits.

         5.       Opinion re Legality

         23.1     Consent of KPMG LLP regarding Form 11-K

         23.2     Consent of KPMG LLP regarding Form 10-K

         23.3     Consent of Brunini, Grantham Grower & Hewes, PLLC

         99.      Undertaking
SIGNATURES

Pursuant to the  requirements  of the  Securities  Act of 1933, as amended,  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  Post
Effective  Amendment  to be signed on its behalf by the  undersigned,  thereunto
duly authorized, in the City of Jackson and State of Mississippi on the 27th day
of October, 2003.

                              TRUSTMARK CORPORATION

                              /s/ Richard G. Hickson
                              ----------------------
                              Richard G. Hickson
                              President and Chief Executive Officer

Pursuant to the  requirements  of the Securities  Act of 1933, as amended,  this
Post  Effective  Amendment  to  Registration  Statement  has been  signed by the
following persons in the capacities and on the date indicated.

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

/s/ Richard G. Hickson                                          October 27, 2003
----------------------
Richard G. Hickson             Chairman, President and Chief
                               Executive Officer (Principal
                               Executive Officer), Director

/s/ Zach L. Wasson             Treasurer (Principal Financial   October 27, 2003
------------------             Officer)
Zach L. Wasson

/s/ Louis E. Greer             Chief Accounting Officer         October 27, 2003
------------------
Louis E. Greer                 (Principal Accounting Officer)

/s/ J. Kelly Allgood           Director                         October 27, 2003
--------------------
J. Kelly Allgood
/s/ Reuben V. Anderson         Director                         October 27, 2003
----------------------
Reuben V. Anderson

                               Director
-----------------
John L. Black, Jr.

/s/ William C. Deviney,  Jr.   Director                         October 27, 2003
----------------------------
William C. Deviney, Jr.

/s/ C. Gerald Garnett          Director                         October 27, 2003
---------------------
C. Gerald Garnett

/s/ Matthew L. Holleman III    Director                         October 27, 2003
---------------------------
 Matthew L. Holleman III

/s/ William Neville III        Director                         October 27, 2003
-----------------------
William Neville III

/s/ Richard H. Puckett         Director                         October 27, 2003
----------------------
Richard H. Puckett

/s/ Carolyn C. Shanks          Director                         October 27, 2003
---------------------
Carolyn C. Shanks

/s/ Kenneth W. Williams        Director                         October 27, 2003
------------------------
Kenneth W. Williams

/s/ William G. Yates,  Jr.     Director                         October 27, 2003
--------------------------
William G. Yates, Jr.
BRUNINI, GRANTHAM, GROWER & HEWES, PLLC

TELEPHONE                  ATTORNEYS AT LAW                   MAILING ADDRESS
(601) 948-3101         1400 TRUSTMARK BUILDING            POST OFFICE DRAWER 119
                       248 EAST CAPITOL STREET        JACKSON, MISSISSIPPI 39205
FACSIMILE            JACKSON, MISSISSIPPI 39201
(601) 960-6902

Exhibit 5

                                October 28, 2003

The Board of Directors of
Trustmark Corporation
248 East Capitol Street
Jackson, Mississippi 39201

Ladies and Gentlemen:

     We  have  acted  as  counsel  to  Trustmark   Corporation,   a  Mississippi
corporation (the "Company") and its 401(k) Plan (the "Plan"), in connection with
a Post  Effective  Amendment  to a  Registration  Statement  on Form  S-8  (File
No.333-07141)  with respect to the  Company's  common  stock,  no par value (the
"Common  Securities") being offered pursuant to the Plan as well as interests in
the Plan.

     We have reviewed such corporate records,  certificates and other documents,
and such questions of law, as we have  considered  necessary or appropriate  for
the purposes of this  opinion.  We have assumed that each of the parties  (other
than the Company) has duly  authorized,  executed and delivered the documents to
which it is a party.

     We have relied as to certain  matters on  information  obtained from public
officials,  officers  of the  Company,  and other  sources  believed by us to be
responsible.

     Based  upon the  foregoing,  and  subject to the  qualifications  set forth
below, we are of the opinion that:

(1). The Company is a corporation  duly  incorporated,  validly  existing and in
     good standing under the laws of the State of Mississippi.

(2). When issued, such Common Securities will be validly issued,  fully paid and
     nonassessable.

     The foregoing opinion is subject to the  qualifications  that we express no
     opinion as to (i) waivers of defenses or statutory or constitutional rights
     or waivers of unmatured claims or rights,  (ii) rights to  indemnification,
     contribution  or  exculpation  to the extent that they purport to indemnify
     any party against,  or release or limit any party's  liability for, its own
     breach or failure to comply with  statutory  obligations,  or to the extent
     such  provisions  are  contrary  to  public  policy,  or  (iii)  rights  to
     collection of liquidated damages or penalties.

     We are members of the bar of the State of Mississippi. We do not purport to
     be experts  in, and do not  express any opinion on, any laws other than the
     law of the State of Mississippi and the Federal law of the United States of
     America.

                                    Very truly yours,

                                    Brunini, Grantham, Grower & Hewes, PLLC

                                    /s/ Robert D. Drinkwater
                                    ------------------------
                                    Robert D. Drinkwater
Exhibit 23.1

                          Independent Auditors' Consent

The Board of Directors
Trustmark Corporation:

We  consent to the use of our report  dated  June 6, 2003,  with  respect to the
financial  statements and supplemental  schedule of Trustmark 401 (k) Plan as of
December 31, 2002 and 2001,  and for the year ended  December  31,  2002,  which
report  appears in the December 31, 2002 annual report on Form 11-K of Trustmark
401 (k) Plan, incorporated by reference herein.

                                  /s/ KPMG LLP
                                  ------------
Jackson, Mississippi
October 27, 2003
Exhibit 23.2

                          Independent Auditors' Consent

The Board of Directors
Trustmark Corporation:

We consent to the use of our report dated January 20, 2003,  with respect to the
consolidated balance sheets of Trustmark Corporation as of December 31, 2002 and
2001,   and  the  related   consolidated   statements  of  income,   changes  in
shareholders'  equity  and cash  flows for each of the  years in the  three-year
period ended  December 31, 2002,  which report  appears in the December 31, 2002
annual report on Form 10-K of Trustmark  Corporation,  incorporated by reference
herein.  Our report refers to changes in the method of accounting for derivative
instruments, hedging activities, goodwill and other intangible assets.

                                  /s/ KPMG LLP
                                  ------------
Jackson, Mississippi
October 27, 2003
Exhibit 23.3

               CONSENT OF BRUNINI, GRANTHAM, GROWER & HEWES, PLLC

We hereby  consent to the inclusion of our opinion in Post  Effective  Amendment
No. 1 to the Registration Statement  (Registration Number 333-07141) on Form S-8
of Trustmark Corporation filed on or about October 29, 2003 and to the filing of
our legal (Exhibit 5) opinion as an Exhibit to such Registration Statement.

                                  BRUNINI, GRANTHAM, GROWER & HEWES, PLLC

                                  /s/ Robert D. Drinkwater
                                  ------------------------
                                  Robert D. Drinkwater

Jackson, Mississippi
October 28, 2003
Exhibit 99.1

Registrant  undertakes  that it will  submit or has  submitted  the Plan and any
amendments  thereto to the Internal  Revenue  Service ("IRS") in a timely manner
and has made or will make all  changes  required  by the IRS in order to qualify
the Plan.