UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                  SCHEDULE 13G
                    Under the Securities Exchange Act of 1934
                              (Amendment No. 2003)

                              TRUSTMARK CORPORATION
                                (Name of Issuer)

                                  COMMON STOCK
                         (Title of Class of Securities)

                                    898402102
                                 (CUSIP Number)

                                December 31, 2003
             (Date of Event Which Requires Filing of this Statement)


Check the  appropriate box to designate the rule pursuant to which this Schedule
is filed:

                               [X] Rule 13d-1(b)
                               [ ] Rule 13d-1(c)
                               [ ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).



CUSIP No. 898402102

1.  NAME OF REPORTING PERSON
    I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

       Trustmark National Bank, as trustee
       64-0180810

2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

    (a) [ ]
    (b) [ ]

3.  SEC USE ONLY


4.  CITIZENSHIP OR PLACE OF ORGANIZATION

    Organized under the laws of the United States

NUMBER OF              5.   SOLE VOTING POWER           1,724,423
SHARES
BENEFICIALLY           6.   SHARED VOTING POWER           159,673
OWNED BY
EACH                   7.   SOLE DISPOSITIVE POWER      1,724,423
REPORTING
PERSON                 8.   SHARED DISPOSITIVE POWER      159,673
WITH

9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

    1,884,096

10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

    [ ]

11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

    3.2%

12. TYPE OF REPORTING PERSON

    BK



CUSIP No. 898402102

Item 1(a)  Name of Issuer:

           Trustmark Corporation

Item 1(b)  Address of Issuer's Principal Executive Offices:

           248 East Capitol Street
           Jackson, Mississippi 39201

Item 2(a)  Name of Person Filing:

           Trustmark National Bank, as trustee

Item 2(b)  Address of Principal Business Office:

           248 East Capitol Street
           Jackson, Mississippi 39201

Item 2(c)  Citizenship:

           Organized under the laws of the United States

Item 2(d)  Title of Class of Securities:

           Common Stock

Item 2(e)  CUSIP Number:

           898402102

Item 3     Type of Person:

           (b) Bank [x] Bank as defined in section 3(a)(6) of the Act
               (15 U.S.C. 78c).

Item 4     Ownership:

           (a) Amount beneficially owned: 1,884,096
           (b) Percent of class: 3.2%
           (c) Number of shares as to which the person has:
                 (i) Sole power to vote or to direct the vote
                     1,724,423

                (ii) Shared power to vote or to direct the vote
                     159,673

               (iii) Sole power to dispose or to direct the disposition of
                     1,724,423

                (iv) Shared power to dispose or to direct the disposition of
                     159,673

Item 5     Ownership of Five Percent or Less of a Class:

           N/A



CUSIP No. 898402102

Item 6    Ownership of More than Five Percent on Behalf of Another Person:

     The shares referred to in this Schedule 13G are held by Trustmark  National
Bank as trustee of various trust accounts. Trustmark National Bank does not have
the right to receive the dividends from these shares or to receive proceeds from
the sale of these shares. Trustmark National Bank is not aware of any individual
trust or  beneficiary or related group of trusts or  beneficiaries  who own more
than 5% of this stock.

Item 7     Identification and Classification of  the  Subsidiary Which  Acquired
           the Security Being Reported on by the Parent Holding Company:

           N/A

Item 8     Identification and Classification of Members of the Group:

           N/A

Item 9     Notice of Dissolution of Group:

           N/A

Item 10    Certification:

     By signing  below I certify  that,  to the best of my knowledge and belief,
the  securities  referred to above were  acquired  and are held in the  ordinary
course of business  and were not acquired and are not held for the purpose of or
with the effect of  changing  or  influencing  the  control of the issuer of the
securities  and were not  acquired and are not held in  connection  with or as a
participant in any transaction having that purpose or effect.

Signature:

     After  reasonable  inquiry and to the best of my  knowledge  and belief,  I
certify that the information  set forth in this statement is true,  complete and
correct.

Date:      February 13, 2004

Signature: /s/ Louis E. Greer
           ------------------

Name and Title:
           Louis E. Greer
           Senior Vice President
           And Chief Accounting Officer