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    58,407,080 SHARES OF SERIES A 8% CUMULATIVE CONVERTIBLE PREFERRED STOCK
                           OFFERED PURSUANT TO RIGHTS
                          DISTRIBUTED TO SHAREHOLDERS
                                  OF MESA INC.
 
To Securities Dealers, Commercial Banks,
Trust Companies and Other Nominees:
 
     This letter is being distributed to securities dealers, commercial banks,
trust companies and other nominees in connection with the offering by MESA Inc.
("Mesa") of an aggregate of approximately 58,407,080 shares of Series A 8%
Cumulative Convertible Preferred Stock, par value $.01 per share ("Series A
Preferred Stock"), of Mesa, at a subscription price of $2.26 per share of Series
A Preferred Stock (the "Subscription Price"), pursuant to the exercise of
transferable rights (the "Rights") initially distributed to all holders of
record of shares of Mesa's Common Stock, par value $.01 per share, ("Common
Stock") as of the close of business on             , 1996 (the "Record Date").
Each Right also carries the right to "oversubscribe" at the Subscription Price
for shares of Series A Preferred Stock that are not otherwise purchased pursuant
to the exercise of Rights. The Rights are described in the enclosed Prospectus
and evidenced by a Subscription Certificate registered in your name or the name
of your nominee.
 
     Each beneficial owner of shares of Common Stock registered in your name or
the name of your nominee is entitled to .912 Rights for each share of Common
Stock owned by such beneficial owner.
 
     We are asking you to contact your clients for whom you hold shares of
Common Stock registered in your name or in the name of your nominee to obtain
instructions with respect to the Rights.
 
     Enclosed are copies of the following documents:
 
     1. The Prospectus:
 
     2. A form of Notice of Guaranteed Delivery for Subscription Certificates
        issued by MESA Inc.;
 
     3. A return envelope addressed to The American Stock Transfer & Trust
        Company, as Subscription Agent;
 
     4. A DTC Participation Oversubscription Exercise Form;
 
     5. A Nominee Holder Certification; and
 
     6. A form of Certification and Request for Additional Rights.
 
     Your prompt action is requested. The Rights will expire at 5:00 P.M., New
York City time, on                , 1996, unless extended by Mesa (as it may be
extended, the "Expiration Date").
 
     To exercise Rights, properly completed and executed Subscription
Certificates and payment in full for all Rights exercised must be delivered to
the Subscription Agent as indicated in the Prospectus prior to the Expiration
Date, unless the guaranteed delivery procedures described in the Prospectus are
followed.
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     Additional copies of the enclosed materials may be obtained from Morrow &
Co., Inc., the Information Agent for the Rights Offering. The Information
Agent's toll-free telephone number is (800) 566-9061.
 
                                        Very truly yours,
 
                                        MESA INC.
 
NOTHING HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU OR ANY PERSON
AS AN AGENT OF MESA INC., THE SUBSCRIPTION AGENT OR ANY OTHER PERSON MAKING OR
DEEMED TO BE MAKING OFFERS OF THE SERIES A 8% CUMULATIVE CONVERTIBLE PREFERRED
STOCK ISSUABLE UPON VALID EXERCISE OF THE RIGHTS, OR AUTHORIZE YOU OR ANY OTHER
PERSON TO MAKE ANY STATEMENTS ON BEHALF OF ANY OF THEM WITH RESPECT TO THE
OFFERING EXCEPT FOR STATEMENTS MADE IN THE PROSPECTUS.
 
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