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                                                                    Exhibit 99.3

                                 [LOGO] HARKEN
                               Energy Corporation

                             Shares of Common Stock

                           Offered Pursuant to Rights

                         Distributed to Security Holders

                 , 2003
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Dear Security Holder:

     This notice is being distributed by Harken Energy Corporation (the
"Company") to all holders of record of shares of its common stock, par value
$0.01 per share (the "Common Stock"), and holders of record of shares of its
Series G1 preferred stock and Series G2 preferred stock (collectively, the
"Preferred Stock") at the close of business on               , 2003 (the "Record
                                               --------------
Date"), in connection with a distribution in a rights offering (the "Rights
Offering") of non-transferable subscription rights (the "Rights") to subscribe
for and purchase shares of its Common Stock. The Rights are described in the
Company's Prospectus dated                , 2003 (the "Prospectus").
                           ---------------

     In the Rights Offering, the Company is offering an aggregate of
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shares of Common Stock (the "Underlying Shares"), as described in the
Prospectus.

     The Rights will expire, if not exercised, at 5:00 p.m., New York City time,
on               , 2003, unless extended in the sole discretion of the Company
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(as it may be extended, the "Expiration Date").

         As described in the Prospectus, you will receive one Right for each
share of Common Stock owned (or in the case of Preferred Stock, one Right for
each share of Common Stock issuable upon conversion) of record as of the close
of business on the Record Date.

     Each Right allows you to subscribe for       shares of Common Stock. The
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Subscription Price for the Rights is $    per Right (or $    per share of Common
                                      ---                ---
Stock) (the "Subscription Right").

     If any shares of Common Stock offered in the Rights Offering remain
unsubscribed after the Rights Offering, Lyford Investments Enterprises Ltd., a
creditor of the Company, has agreed to purchase all shares at the Subscription
Price.

     The Rights will be evidenced by non-transferable Rights certificate (the
"Rights Certificate") and will cease to have any value at the close of business
on the Expiration Date.

     Enclosed are copies of the following documents:

     1.   Prospectus;

     2.   Rights Certificate;

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     3.   Instructions as to Use of Harken Energy Corporation Rights
          Certificates (including a Notice of Guaranteed Delivery for Rights
          Certificates Issued by Harken Energy Corporation and Guidelines for
          Request for Taxpayer Identification Number and Certification on
          Substitute Form W-9); and

     4.   A return envelope addressed to American Stock Transfer & Trust
          Company, the Subscription Agent.

     Your prompt action is requested. To exercise Rights, you should properly
complete and sign the Rights Certificate (or the Notice of Guaranteed Delivery
if you are following the Guaranteed Delivery Procedures) and forward it, with
payment of the Subscription Price in full for each share of Common Stock
subscribed for pursuant to the Subscription Right, to the Subscription Agent, as
indicated in the Prospectus. The Subscription Agent must receive the Rights
Certificate or Notice of Guaranteed Delivery with payment of the Subscription
Price prior to 5:00 p.m., New York City time, on the Expiration Date. A Rights
holder cannot revoke the exercise of its Rights. Rights not exercised prior to
the Expiration Date will expire.

     Additional copies of the enclosed materials may be obtained from the
Subscription Agent. The Subscription Agent's telephone number is (718) 921-8237.

                                                  Very truly yours,

                                                  HARKEN ENERGY CORPORATION

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