USG CORPORATION
                    PLEASE MARK VOTE IN OVALS IN THE FOLLOWING MANNER USING DARK INK ONLY. |_|

THE BOARD OF DIRECTORS RECOMMENDS A VOTE FOR ITEMS 1 AND 2.
                                                                                         
1.  Election of Directors to serve for a three year term        For             Withheld          For All
     Nominees: 01 - Robert L. Barnett, 02 -  David W. Fox,      All               All             Except
     03 - Valerie B. Jarrett, 04 - Marvin E. Lesser.            |_|               |_|              |_|


- ----------------------------------------------
                Nominee Exception(s)


2.  Ratification of the appointment of Arthur Andersen LLP as   For             Against          Abstain
     independent public accountants for the year ending Decemb  |_|               |_|              |_|
     31, 1999.


3.   In their discretion,  on any other matter that may properly come before the
     meeting.

I plan to attend the Annual Meeting                             |_|


Dated:



- ---------------------------
Signature


- ---------------------------
Signature

The signature above should agree with the name shown on this Proxy.  Where stock is owned by more than one person, all owners
should sign the Proxy.

This proxy will be voted as directed or, if no direction is  indicated,  it will
be voted for all  candidates  named in Item 1 and for Item 2.



Control Number                      Fold and Detach Here USG CORPORATION
                                              VOTE BY TELEPHONE
[insert box here]                   Call Toll Free On a Touch Tone Phone

                                      1-877-587-0756 - 24 Hours a Day
                                   There is NO CHARGE to you for this call

Your  telephone  vote  authorizes  the  proxies to vote your  shares in the same
manner as if you marked, signed and returned your proxy card.

You will be asked to enter a Control  Number  which is located in the box on the
left side of this form.

OPTION #1: To vote as the Board of Directors recommends on ALL proposals: Press 1
                  WHEN ASKED, PLEASE CONFIRM YOUR VOTE BY PRESSING 1 - THANK YOU FOR VOTING
OPTION #2: If you choose to vote on each proposal separately, press 0.  You will hear these instructions:
               
         Proposal 1:  To vote FOR ALL nominees, press 1; to WITHHOLD FOR ALL nominees, press 9
                    To WITHHOLD FOR AN INDIVIDUAL nominee, Press 0 and listen to the instructions

         Proposal 2: To vote FOR, press 1; AGAINST, press 9; ABSTAIN, press 0

         WHEN  ASKED,  PLEASE  CONFIRM  YOUR VOTE BY  PRESSING 1 - THANK YOU FOR
VOTING.

                             If you  vote by  telephone,  DO NOT  mail  your proxy.


PROXY                          USG CORPORATION                             PROXY



This  proxy is  solicited  on behalf of the Board of  Directors  for the  Annual
Meeting of Stockholders - May 12, 1999


The undersigned hereby appoints William C. Foote and Dean H. Goossen and each or
any of  them,  attorneys,  with  power  of  substitution  and  with  powers  the
undersigned  would  possess  if  personally  present,  to vote all  stock of the
undersigned in USG  CORPORATION at the annual  meeting of  stockholders  of said
Corporation in the Sixth Floor Auditorium, The Northern Trust Building, 50 South
LaSalle Street, Chicago, Illinois on May12, 1999 and any adjournment thereof, on
the matters  shown below and as set forth in the  accompanying  Notice of Annual
Meeting of Stockholders and Proxy Statement.


            PLEASE MARK, SIGN, DATE AND MAIL THIS PROXY CARD PROMPTLY
          USING THE ENCLOSED ENVELOPE - EXCEPT IF YOU VOTE BY TELEPHONE



Please  indicate any change in address.  (Continued  and to be signed on reverse
side.)


















Dear Shareholder:

On the reverse  side of this card are  instructions  that allow you to vote your
shares  for the  election  of  directors  and all other  proposals  TOLL FREE by
telephone.  Please consider voting by telephone.  Your vote is recorded the same
as if you mailed in your proxy card.  Telephone  voting is designed to be quick,
convenient and FREE OF CHARGE to you.





                                                  USG CORPORATION
                    PLEASE MARK VOTE IN OVALS IN THE FOLLOWING MANNER USING DARK INK ONLY. |_|

THE BOARD OF DIRECTORS RECOMMENDS A VOTE FOR ITEMS 1 AND 2.
                                                                                   
1.  Election of Directors to serve for a three year term        For      Withheld   For All
     Nominees:  Robert L. Barnett, David W. Fox,                All       All       Except
     Valerie B. Jarrett, Marvin E. Lesser.                      |_|       |_|        |_|


     ----------------------------------------
                Nominee Exception(s)


2.  Ratification  of the  appointment  of  Arthur  Andersen  LLP as       For        Against   Abstain
    independent public accountants for the year ending December           |_|         |_|       |_|
    31, 1999.


3.  In their  discretion,  on any other matter that may properly come before the
    meeting.

    I plan to attend the Annual Meeting.                         |_|


Dated:



- --------------------------------
Signature


- --------------------------------
Signature

The signature above should agree with the name shown on this Proxy.  Where stock is owned by more than one person, all owners
should sign the Proxy.


This proxy will be voted as directed or, if no direction is indicated, it will be voted for all candidates named in Item 1
and for Item 2.


PROXY                            USG CORPORATION                           PROXY



This  proxy is  solicited  on behalf of the Board of  Directors  for the  Annual
Meeting of Stockholders - May 12, 1999


The undersigned hereby appoints William C. Foote and Dean H. Goossen and each or
any of  them,  attorneys,  with  power  of  substitution  and  with  powers  the
undersigned  would  possess  if  personally  present,  to vote all  stock of the
undersigned in USG  CORPORATION at the annual  meeting of  stockholders  of said
Corporation in the Sixth Floor Auditorium, The Northern Trust Building, 50 South
LaSalle Street, Chicago, Illinois on May12, 1999 and any adjournment thereof, on
the matters  shown below and as set forth in the  accompanying  Notice of Annual
Meeting of Stockholders and Proxy Statement.


            PLEASE MARK, SIGN, DATE AND MAIL THIS PROXY CARD PROMPTLY
                           USING THE ENCLOSED ENVELOPE



Please  indicate any change in address.  (Continued  and to be signed on reverse
side.)