11-K/A

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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                                   FORM 11-K/A

                                 Amendment No. 1


(Mark One)

   X              ANNUAL REPORT PURSUANT TO SECTION 15 (d) OF THE SECURITIES
                  EXCHANGE ACT OF 1934 FOR THE FISCAL YEAR ENDED DECEMBER 31,
                  2002

                                       OR


                  TRANSITION REPORT PURSUANT TO SECTION 15 (d) OF THE SECURITIES
                  EXCHANGE ACT OF 1934

For the transition period from          to

Commission file number: 1-8864

A. Full title of plan and the address of the plan, if different from that of the
   issuer named below:

                  USG CORPORATION INVESTMENT PLAN

B. Name of issuer of the securities held pursuant to the plan and the address of
   its principal executive office:

                  USG Corporation
                  125 South Franklin Street
                  Chicago, IL  60606-4678


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                                TABLE OF CONTENTS

Explanatory Note
Signatures
Exhibit Index
Exhibit 23
Exhibit 99.1



EXPLANATORY NOTE

This Form 11-K/A amends the Form 11-K of the USG Corporation Investment Plan
(formerly the USG Corporation Investment Plan for Salaried Employees) filed on
March 28, 2003, for the purposes of including the Consent of the Independent
Public Accountants attached hereto as Exhibit 23 and the Certification Pursuant
to 18 U.S.C. Section 1350 attached hereto as Exhibit 99.1.



                                    SIGNATURE


The Plan. Pursuant to the requirements of the Securities Exchange Act of 1934,
the USG Corporation Pension and Investment Committee has duly caused this
amendment to its annual report to be signed on its behalf by the undersigned
hereunto duly authorized.


                                    USG CORPORATION INVESTMENT PLAN


                                    By:  /s/ Peter K. Maitland
                                         ------------------------------
                                         Peter K. Maitland,
                                         Plan Administrator




Date:  June 30, 2003



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                                  EXHIBIT INDEX

Exhibit No.             Description

Exhibit 23              Consent of Independent Accountants.

Exhibit 99.1            Certification of Richard H. Fleming, Chairman of the USG
                        Corporation Pension and Investment Committee and Peter
                        K. Maitland, Plan Administrator.

EX-23

                                                                      EXHIBIT 23

                       CONSENT OF INDEPENDENT ACCOUNTANTS
                            WITH RESPECT TO FORM S-8

As independent auditors, we hereby consent to the incorporation by reference of
our report, dated March 14, 2003, appearing in the USG Corporation Investment
Plan Annual Report on Form 11-K, for the year ended December 31, 2002, into USG
Corporation's previously filed Registration Statements No. 2-94787, 33-63554 and
33-9948 on Form S-8. It should be noted that we have not examined any financial
statements of the Investment Plan subsequent to December 31, 2002, or performed
any audit procedures subsequent to the date of our report.

/s/  Hill Taylor LLC

Hill Taylor, LLC
Chicago, Illinois
March 28, 2003

EX-99.1

                                                                    EXHIBIT 99.1

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002


         In connection with the Annual Report of the USG Corporation Investment
Plan (the "Plan") on Form 11-K for the year ended December 31, 2002, as filed
with the Securities and Exchange Commission on March 28, 2002, and as amended on
the date hereof (the "Report"), the undersigned, the Plan Administrator, and the
Chairman of the USG Corporation Pension and Investment Committee, certify
pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002 ("Section 906"), to the best of their knowledge,
that:

         (1)      The Report fully complies with the requirements of Section 13
                  (a) of the Securities Exchange Act of 1934 (15 U.S.C. 78m);
                  and

         (2)      The information contained in the Report fairly presents, in
                  all material respects, the statements of net assets available
                  for benefits and the statements of changes in net assets
                  available for benefits of the Plan.

June 30, 2003

                              By:  /s/ Peter K. Maitland
                                   --------------------------------
                                    Peter K. Maitland,
                                    Plan Administrator

                              By:  /s/ Richard H. Fleming
                                   --------------------------------
                                    Richard H. Fleming,
                                    Chairman of the USG Corporation
                                    Pension and Investment Committee


A signed original of this written statement required by Section 906 has been
provided to the Plan and will be retained by the Plan and furnished to the
Securities and Exchange Commission or its staff upon request.