<PAGE>   1

     As filed with the Securities and Exchange Commission on June 26, 1998
                                                      Registration No. _________
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549
                              ____________________

                                    FORM S-3
            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
                              ____________________

                           HARKEN ENERGY CORPORATION
             (Exact name of registrant as specified in its charter)
                              ____________________

           DELAWARE                                      95-2841597
(State or other jurisdiction of          (I.R.S. employer identification number)
incorporation or organization)

                           HARKEN ENERGY CORPORATION
                     5605 NORTH MACARTHUR BLVD., SUITE 400
                              IRVING, TEXAS 75038
                                 (972) 753-6900
              (Address, including zip code, and telephone number,
       including area code, of registrant's principal executive offices)
                        ________________________________

                               LARRY E. CUMMINGS
                       VICE PRESIDENT AND GENERAL COUNSEL
                           HARKEN ENERGY CORPORATION
                     5605 NORTH MACARTHUR BLVD., SUITE 400
                              IRVING, TEXAS 75038
                                 (972) 753-6900
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
                        ________________________________

APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:  From time to
time after the effective date of this Registration Statement.
                        ________________________________

       If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box: [ ]

       If any of the securities being registered on this Form are to be offered
on a delayed or continuous basis pursuant to Rule 415 under the Securities Act
of 1933, other than securities offered only in connection with dividend or
interest reinvestment plans, check the following box: [X]

       If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following
box and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering:  [ ] __________________

       If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering:  [ ] ______________________

       If delivery of the Prospectus is expected to be made pursuant to Rule
434, please check the following box:  [ ]

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
=================================================================================================================================
                                                              Proposed Maximum
                                               Amount             Aggregate            Proposed Maximum          Amount of
       Title of each Class of Shares            to be        Price Per Security       Aggregate Offering        Registration
             to be Registered                Registered              (1)                   Price (1)              Fee (1)
---------------------------------------------------------------------------------------------------------------------------------
  <S>                                        <C>               <C>                      <C>                        <C>
  Common Stock, par value $0.01 per          13,977,446            $4.91                 $68,629,259.86            $20,246
  share
=================================================================================================================================
</TABLE>


(1) Estimated solely for the purpose of calculating the registration fee
    pursuant to Rule 457(c) based on the average of the high and low sales
    prices of the common stock as reported by the American Stock Exchange on
    June 25, 1998.

(2) In accordance with Rule 457(g), no additional registration fee is required
    in respect of the Preferred Stock Purchase Rights.

THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR DATES
AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL FILE
A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION STATEMENT
SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF THE
SECURITIES ACT OF 1933, OR UNTIL THIS REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.
================================================================================
<PAGE>   2
INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT.  A
REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION.  THESE SECURITIES MAY NOT BE SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT BECOMES
EFFECTIVE.  THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE SECURITIES
IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.

                   SUBJECT TO COMPLETION DATED JUNE 26, 1998

                                   PROSPECTUS
                               13,977,466 Shares

                           HARKEN ENERGY CORPORATION

                                  Common Stock
                              ____________________

      The 13,977,466 shares (the "Shares") of common stock, par value $0.01 per
share ("Common Stock"), of Harken Energy Corporation, a Delaware corporation
("Harken" or the "Company"), offered hereby are being offered by the
stockholders of the Company described herein (the "Selling Stockholders").  The
Common Stock includes the preferred stock purchase rights attaching to such
stock pursuant to that certain Rights Agreement dated as of April 6, 1998, by
and between Harken and ChaseMellon Shareholder Services L.L.C.  The Company
will not receive any of the proceeds from the sale of the Shares, but the
Company has agreed to bear certain expenses of registration of the Shares under
the federal and state securities laws (currently estimated to be $30,000).
See "Selling Stockholders" and "Use of Proceeds."

      The Common Stock is traded on the American Stock Exchange, under the
symbol "HEC."  On June 25, 1998, the closing sales price of the Common Stock as
reported on the American Stock Exchange was $5.00 per share.

      The Shares may be offered and sold from time to time by the Selling
Stockholders or their respective pledges, donees, transferees or other
successors in interest directly or through broker-dealers or underwriters who
may act solely as agents, or who may acquire the Shares as principals.  The
distribution of the Shares may be effected in one or more transactions that may
take place through the American Stock Exchange or on such other market on which
the Common Stock may from time to time be trading, including block trades or
ordinary broker's transactions, or through privately negotiated transactions,
or through the writing of options on the shares or short sales, through an
underwritten public offering, or through a combination of any such methods of
sale, at such prices as may be obtainable.  Usual and customary or specially
negotiated brokerage fees or commissions may be paid by the Selling
Stockholders in connection with such sales.  See "Plan of Distribution."

      To the extent required, the specific shares of Common Stock to be sold,
the purchase price, public offering price, names of any agent, dealer or
underwriter, and any applicable commission or discount with respect to a
particular offering will be set forth in an accompanying Prospectus Supplement.
The aggregate proceeds to the Selling Stockholders from the sale of the Shares
will be the purchase price thereof less the aggregate agents' commissions and
underwriters' discounts, if any, and other expenses of distribution not borne
by the Company.

      The Selling Stockholders and any broker-dealers, agents or underwriters
that participate with the Selling Stockholders in the distribution of any of
the Shares may be deemed to be "underwriters" within the meaning of the
Securities Act of 1933, as amended (the "Securities Act"), and any commission
received by them and any profit on the resale of the Shares purchased by them
may be deemed to be underwriting commissions or discounts under the Securities
Act.  See "Plan of Distribution" for indemnification arrangements.

      PROSPECTIVE INVESTORS SHOULD CONSIDER AND REVIEW THE INFORMATION UNDER
THE CAPTION "RISK FACTORS" BEGINNING ON PAGE 4 PRIOR TO AN INVESTMENT IN THE
SHARES OFFERED HEREBY.
                              ____________________

THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS.  ANY REPRESENTATION TO THE CONTRARY IS
A CRIMINAL OFFENSE.
                              ____________________

                 The date of this Prospectus is June 26, 1998.
<PAGE>   3
                             AVAILABLE INFORMATION

      The Company is subject to the informational requirements of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in
accordance therewith files reports, proxy statements and other information with
the Securities and Exchange Commission (the "Commission").  Such reports, proxy
statements and other information filed by the Company may be inspected and
copied, at prescribed rates, at the public reference facilities of the
Commission at 450 Fifth Street, N.W., Washington, D.C. 20549, Room 1024, as
well as at the regional offices of the Commission at Seven World Trade Center,
13th Floor, New York, New York 10048, and Northwestern Atrium Center, 500 West
Madison Street, Suite 1400, Chicago, Illinois 60601.  Copies of such material
may also be obtained at prescribed rates by writing to the Public Reference
Section of the Commission at 450 Fifth Street, N.W., Washington, D.C. 20549.
Such documents are also available at the Web site maintained by the Commission
(http://www.sec.gov).  The Common Stock is listed on the American Stock
Exchange.  Reports, proxy statements and other information described above may
also be inspected and copied at the offices of the American Stock Exchange at
86 Trinity Place, New York, New York 10006.

      The Company has filed with the Commission a registration statement on
Form S-3 (the "Registration Statement") under the Securities Act, with respect
to the Shares offered hereby.  This Prospectus, which constitutes a part of the
Registration Statement, does not contain all the information set forth in the
Registration Statement and the exhibits thereto.  For further information with
respect to the Company and the Common Stock, reference is hereby made to such
Registration Statement and exhibits.  Statements contained herein concerning
the provisions of any documents are necessarily summaries of those documents,
and each statement is qualified in its entirety by reference to the copy of the
applicable document filed with the Commission.  The Registration Statement and
any amendments thereto, including exhibits filed as a part thereof, are
available for inspection and copying as set forth above.


                               TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                                                     Page
                                                                                                                     ----
<S>                                                                                                                    <C>
Available Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .       2
Incorporation of Certain Documents by Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .       3
The Company . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .       4
Risk Factors  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .       4
Use of Proceeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .       9
Selling Stockholders  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      10
Plan of Distribution  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      11
Legal Matters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      12
Experts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      12
</TABLE>


      NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATIONS OTHER THAN THOSE CONTAINED IN THIS PROSPECTUS, AND, IF GIVEN OR
MADE, SUCH INFORMATION OR REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING
BEEN AUTHORIZED BY THE COMPANY, THE SELLING STOCKHOLDERS OR ANY OTHER PERSON.
THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL OR A SOLICITATION OF AN
OFFER TO BUY ANY SECURITIES OTHER THAN THE SECURITIES TO WHICH IT RELATES OR
ANY OFFER TO SELL OR SOLICITATION OF AN OFFER TO BUY SUCH SECURITIES IN ANY
CIRCUMSTANCES IN WHICH SUCH OFFER OR SOLICITATION IS UNLAWFUL.  NEITHER THE
DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL, UNDER ANY
CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE HAS BEEN NO CHANGE IN THE
AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF OR THAT THE INFORMATION CONTAINED
HEREIN IS CORRECT AS OF ANY TIME SUBSEQUENT TO ITS DATE.


                                       2
<PAGE>   4
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

      The following documents which have been filed with the Commission are
incorporated herein by reference:

      (1)  The Company's Annual Report on Form 10-K for the year ended December
           31, 1997;
      (2)  The Company's Quarterly Report on Form 10-Q for the quarter ended
           March 31, 1998;
      (3)  The Company's Proxy Statement for the Annual Meeting of Stockholders
           of Harken to be held on June 15, 1998;
      (4)  The description of the Common Stock contained in the Company's
           Registration Statement on Form 8-A, as amended, including all
           amendments and reports filed for the purpose of updating such
           description; and the description of the Company's Preferred Stock
           Purchase Rights as contained in the Company's Registration Statement
           on Form 8-A, filed with the Commission on April 7, 1998, including
           all amendments and reports filed for the purpose of updating such
           description;
      (5)  The Company's Current Report on Form 8-K dated April 7, 1998; and
      (6)  The Company's Current Report on Form 8-K dated May 27, 1998.


      All documents filed by Harken pursuant to Section 13(a), 13(c), 14 or
15(d) of the Exchange Act subsequent to the date of this Prospectus and prior
to the termination of the offering made hereby shall be deemed to be
incorporated by reference in this Prospectus and to be a part hereof from the
date of the filing of such documents.  Any statement contained in this
Prospectus, in a supplement to this Prospectus or in a document incorporated or
deemed to be incorporated by reference herein, shall be deemed to be modified
or superseded for purposes of this Prospectus to the extent that a statement
contained herein, or in any subsequently filed supplement to this Prospectus or
in any document that also is or is deemed to be incorporated by reference
herein, modifies or supersedes such statement.  Any statement so modified or
superseded shall not be deemed, except as so modified or superseded, to
constitute a part of this Prospectus.

      The Company will furnish without charge to each person to whom a copy of
this Prospectus has been delivered, upon written or oral request, a copy of any
or all documents incorporated by reference in this Prospectus, other than
exhibits to such documents unless such exhibits are specifically incorporated
by reference in such documents.  Written or oral requests for such copies
should be directed to Gregory S. Porter, Harken Energy Corporation, 5605 North
MacArthur Blvd., Suite 400, Irving, Texas 75038 (Telephone: (972) 753-6900).





                                       3
<PAGE>   5
                                  THE COMPANY

      Harken is engaged in oil and gas exploration, development and production
operations both domestically and internationally through its various
wholly-owned subsidiaries and joint venture investments.  Harken's domestic
operations include oil and gas exploration and production operations in the
Four Corners Area of Utah, Arizona and New Mexico, the Gulf Coast of Texas, the
Texas Panhandle, the Magnolia region of Arkansas, the Carlsbad region of New
Mexico and St. Martin and LaFourche Parishes, Louisiana.  Harken's
international operations include six exclusive Colombian Association Contracts
between Harken's wholly-owned subsidiary, Harken de Colombia, Ltd., and Empresa
Colombiana de Petroleos, the state-owned oil company of the Republic of
Colombia.

      Harken was incorporated in 1973 in the State of California and
reincorporated in 1979 in the State of Delaware.  Harken's principal offices
are located at 5605 North MacArthur Blvd., Suite 400, Irving, Texas 75038 and
its telephone number is (972) 753-6900.

                                  RISK FACTORS

      Prior to making an investment decision, prospective investors should
consider carefully all of the information set forth in this Prospectus and, in
particular, should evaluate the following risk factors.

VOLATILITY OF HARKEN COMMON STOCK TRADING PRICE

      The daily closing prices of the Common Stock as reported by the American
Stock Exchange has fluctuated significantly over the past 12 months, ranging
from a high of $7.50 per share to a low of $4.50 per share.  Management
believes that the price fluctuations and trading activity in the Common Stock
during the past 12 months are attributable to a number of factors, including
Harken's international exploration activities.  There can be no assurance that
future announcements regarding Harken's international exploration efforts will
not have a substantial adverse effect on the then prevailing market price of
the Common Stock.

LOSSES FROM CONTINUING OPERATIONS

      Harken reported losses from continuing operations for the fiscal years
ended December 31, 1994, 1995 and 1996 in the amounts of $8,211,000, $1,625,000
and $341,000, respectively.  For the fiscal year ended December 31, 1997 and
the three months ended March 31, 1998, Harken reported income of approximately
$189,000 and $84,000, respectively.  There can be no assurance, however, that
Harken will continue to remain profitable.

POTENTIAL DILUTION; EFFECT OF SALES OF COMMON STOCK ON MARKET PRICE

      As of June 16, 1998, there were 130,627,349 shares of Common Stock
outstanding.  Harken has reserved a significant number of shares of Common
Stock for future issuance as described below.  There can be no assurance that
the issuance of the shares of Common Stock which have been reserved for future
issuance will not have a material adverse effect on the then prevailing market
price of the Common Stock.  Furthermore, issuance of the shares of Common Stock
as described below could result in significant dilution to the stockholders of
the Company.

      Between October 1997 and March 1998, Harken entered into three separate
Development Finance Agreements (the "Development Finance Agreements") with
institutional investors (the "Investors"), pursuant to which the Investors
provided $35 million of gross proceeds (the "Payment Amount") to Harken to
finance drilling of three prospects in Colombia.  In exchange, the Investors
received the right to receive future payments from Harken based on Harken's net
profits from the three prospects (the "Participation").  The Investors have the
right, for a period of two years beginning between October 1998 and March 1999,
to convert all or part of





                                       4
<PAGE>   6
the Participation into shares of Common Stock. The number of shares of Common
Stock to be issued upon conversion of the Participation will be equal to the
quotient of (i) the Payment Amount (less any distributions made in respect of
the Participation) plus an amount equal to 15% interest per annum on the net
Payment Amount compounded monthly (the "Invested Amount"), divided by (ii) the
market price of the Common Stock at the time of conversion.  Harken also has
the right to convert the Participation into shares of Common Stock with the
number of shares of Common Stock to be issued to be equal to the quotient of
(i) the Payment Amount (less any distribution made in respect of the
Participation) plus an amount equal to 25% interest per annum on the net
Payment Amount compounded monthly, divided by (ii) the market price of the
Common Stock at the time of conversion. Harken can also elect to pay cash upon
any conversion of the Participation in lieu of issuing shares of Common Stock.
The Development Finance Agreements also require the issuance of additional
shares of Common Stock in the event of a conversion to the extent that the
Investors do not, under certain circumstances, realize the Invested Amount from
the sale of the shares of Common Stock issued upon conversion.

      On April 9, 1998, Harken entered into a Securities Purchase Agreement
with RGC International Investors, LDC ("RGC"), pursuant to which Harken issued
to RGC 15,000 shares of its Series F Convertible Preferred Stock (the "Series F
Preferred") in exchange for $15,000,000.  As of May 27, 1998, 15,000 shares of
Series F Preferred were issued and outstanding.  The Series F Preferred is
convertible into shares of Common Stock at a conversion price based upon the
market price of the Common Stock at the time of conversion.  The number of
shares of Common Stock issuable upon conversion of the Series F Preferred will
also include a premium amount equal to interest calculated on the stated value
($1,000 per share) of the Series F Preferred at 5% per annum.  The Series F
Preferred does not pay dividends.

      During the first six months following the issuance of the Series F
Preferred, RGC can elect to convert the shares of the Series F Preferred into
Common Stock on any day that the closing sales price of the Common Stock on the
American Stock Exchange is equal to or greater that 115% of the "Market Price."
The Market Price is equal to the lower of (a) the lowest average of the closing
bid prices of the Common Stock for any five consecutive trading days during the
22 trading days ending one trading day prior to the conversion date, or (b) the
low closing bid price of the Common Stock over the five trading days ending one
trading day prior to the conversion date.

      During the first nine months following the issuance of the Series F
Preferred, the conversion price will be equal to 103% of the Market Price on
the conversion date.  On January 9, 1999, the conversion price will be fixed at
90% of the average of the closing bid prices of the Common Stock for the
previous 22 trading days.  On February 9, 1999, the conversion price will be
fixed at 90% of the average of the closing bid prices of the Common Stock for
the previous 22 trading days if it would result in a lower conversion price
than that calculated on January 9, 1999.  Any shares of Series F Preferred
outstanding on April 9, 1999, will automatically be converted into shares of
Common Stock at the then applicable conversion price.

      At each election to convert shares of Series F Preferred into Common
Stock, RGC will have the option to purchase from Harken for cash additional
shares of Common Stock equal to the number of shares issued on such conversion
(less any shares issued in respect of the premium amount) at a purchase price
equal to the then applicable conversion price.

      As of June 16, 1998 and at an assumed conversion and exercise price of
$4.50 per share, the Series F Preferred and the related options would have been
convertible or exercisable into approximately 7,600,000 shares of Common Stock,
but this number of shares could prove to be significantly greater in the event
of a decrease in the trading price of the Common Stock.  Purchasers of Common
Stock could therefore experience substantial dilution of their investment upon
conversion of the Series F Preferred and exercise of the related options.





                                       5
<PAGE>   7
      On May 20, 1998, a subsidiary of Harken acquired a majority non-operated
working interest in 33 producing oil and gas wells located in St. Martin Parish
and LaFourche Parish, Louisiana, as well as substantial additional development
and exploratory acreage.  As consideration for these properties, Harken issued
2,716,483 shares of Common Stock to the seller, and Harken may be required to
issue additional shares of Common Stock in the future with a value of up to $4
million, or pay cash, upon the resolution of certain identified contingencies.

      On May 26, 1998, Harken issued $85,000,000 in principal amount of its 5%
Senior Convertible Notes due 2003 (the "1998 Notes").  The 1998 Notes are
convertible into shares of Common Stock by the holders thereof at a conversion
price of $6.50 per share, subject to adjustment, at any time after the earlier
of the business day following the effective date of a registration statement
filed by the Company with the Commission with respect to the shares issuable
upon conversion of the 1998 Notes and the date such shares may be sold pursuant
to Rule 144 under the Securities Act or other exemption from registration under
the Securities Act.  A 3% premium on the number of shares issuable upon
conversion of the 1998 Notes will be payable to holders converting 1998 Notes
prior to November 26, 1998 (the "Effective Date").

      Harken can require conversion of the 1998 Notes at any time after May 26,
1999 if the average of the Market Price (as defined) of the Common Stock over
the Stock Exchange Business Days (as defined) in any 30 consecutive calendar
day period the beginning date of which is on or after May 26, 1998 and the
ending date of which is on or after the Effective Date, has equaled or exceeded
125% of the conversion price.  The 1998 Notes may be redeemed for cash at
Harken's option, upon not less than 30 days notice, at par, in whole or in
part, at any time after May 26, 2002.  Commencing November 26, 2002, Harken may
redeem up to 50% of the 1998 Notes for shares of Common Stock, and on May 26,
2003, Harken may redeem all remaining 1998 Notes for shares of Common Stock.
If Harken elects to redeem the 1998 Notes for shares of Common Stock, each such
note will be redeemed for the number of shares of Common Stock equal to 110% of
the sum of the face value of the note plus interest accrued and unpaid thereon
divided by the average of the Market Price of the Common Stock over the 30
calendar day period immediately preceding the date of notice of such
redemption; provided that if the average of the aggregate Market Price of all
of the outstanding shares of Common Stock over such 30 calendar day period is
less than $500 million, each such note will be redeemed for the number of
shares of Common Stock equal to 115% of the sum of the face value of the note
plus interest accrued and unpaid thereon divided by the average of the Market
Price of the Common Stock over the 30 calendar day period immediately preceding
the date of notice of such redemption.  The shares of Common Stock issuable
upon conversion or redemption of the Notes are being registered pursuant to
this registration statement.

      Harken has reserved additional shares of Common Stock for issuance as
follows: (i) 1,630,624 shares of Common Stock have been reserved for issuance
upon exercise of outstanding warrants; and (ii) 8,959,999 shares of Common
Stock have been reserved for issuance upon exercise of outstanding stock
options and stock options which may be issued pursuant to Harken's existing
stock option plans.

PREFERRED STOCK AUTHORIZED FOR ISSUANCE

      Harken has ten million shares of preferred stock available for issuance.
The Board of Directors is authorized to issue such preferred stock in one or
more series and to set the designations, preferences, powers and relative
rights and restrictions thereof without further approval by the stockholders of
the Company.  Presently, Harken has six series of preferred stock authorized,
and 15,000 shares of Series F Preferred Stock are currently outstanding.  Any
additional shares of preferred stock, if issued, would have certain preferences
over the shares of Common Stock with respect to the payment of dividends and
upon liquidation, dissolution, winding-up and in certain instances, voting.
The Board of Directors of Harken also may authorize additional series of
preferred stock in the future that have similar or additional preferences over
the shares of Common Stock.





                                       6
<PAGE>   8
RISKS RELATED TO INTERNATIONAL OPERATIONS

      Harken presently conducts operations in Colombia and anticipates that it
will conduct significant operations in Colombia in the future.  Foreign
properties, operations or investments may be adversely affected by local
political and economic developments, exchange controls, currency fluctuations,
royalty and tax increases, retroactive tax claims, renegotiation of contracts
with governmental entities, expropriation, import and export regulations and
other foreign laws or policies governing operations of foreign-based companies,
as well as by laws and policies of the United States affecting foreign trade,
taxation and investment.  In addition, as certain of Harken's operations are
governed by foreign laws, in the event of a dispute, Harken may be subject to
the exclusive jurisdiction of foreign courts or may not be successful in
subjecting foreign persons to the jurisdiction of courts in the United States.
Harken may also be hindered or prevented from enforcing its rights with respect
to a governmental instrumentality because of the doctrine of sovereign
immunity.  Exploration and production activities in areas outside the United
States are also subject to the risks inherent in foreign operations, including
loss of revenue, property and equipment as a result of hazards such as
expropriation, nationalization, war, insurrection and other political risks.

      Harken anticipates that full development of the oil and gas reserves in
the contract areas covered by Harken's six Colombian Association Contracts will
take several years and may require extensive production facilities which could
require significant additional capital expenditures.  The ultimate amount of
such expenditures cannot be presently predicted.  Harken anticipates that
amounts required to fund international activities, including those in Colombia,
will be funded from existing cash balances, asset sales, stock issuances,
production payments, operating cash flows and potentially from industry
partners; however, there can be no assurance that Harken will have adequate
funds available to it to fund its international activities without
participation from industry partners or that participation from industry
partners can be obtained to fund such international activities.  In addition,
Harken faces certain deadlines for completing specific projects required
pursuant to the six Colombian Association Contracts.  Failure to meet any of
such deadlines could result in Harken losing its rights to one or more of the
Association Contracts, which could have a material adverse effect on Harken's
business.

UNCERTAINTIES IN UNITED STATES -- COLOMBIA RELATIONS

      Pursuant to the Foreign Assistance Act of 1961, the President of the
United States is required to determine whether to certify that certain
countries have cooperated with the United States, or taken adequate steps on
their own, to achieve the goals of the United Nations Convention Against
Illicit Traffic in Narcotic Drugs and Psychotropic Substances.  In 1995, 1996
and 1997, the President did not certify Colombia.  As a result, the United
States imposed substantial economic sanctions on Colombia, including the
withholding of bilateral economic assistance, the blocking of Export-Import
Bank and Overseas Private Investment Corporation loans and political risk
insurance, and the entry of the United States votes against multilateral
assistance to Colombia in the World Bank and the InterAmerican Development
Bank.

      The consequences of continued and successive United States
decertifications of Colombian activities are not fully known, but may include
the imposition of additional economic sanctions on Colombia in 1998 and
succeeding years.  The President also has authority to impose far-reaching
economic, trade and investment sanctions on Colombia pursuant to the
International Emergency Economic Powers Act of 1978.  The Colombian
government's reaction to United States sanctions could potentially include,
among other things, restrictions on the repatriation of profits and the
nationalization of Colombian assets owned by United States entities.
Accordingly, imposition of the foregoing economic and trade sanctions on
Colombia could materially affect the performance of the Common Stock and the
Company's long-term financial results.





                                       7
<PAGE>   9
INDUSTRY RISKS

      Oil and Gas Price Volatility.  The revenues generated by Harken are
highly dependent upon the prices of crude oil and natural gas.  Fluctuations in
the energy market make it difficult to estimate future prices of oil and
natural gas.  Fluctuations in energy prices are caused by a number of factors,
including regional, domestic and international demand, energy legislation,
federal or state taxes on sales of crude oil and natural gas, production
guidelines established by the Organization of Petroleum Exporting Countries,
and the relative abundance of supplies of alternative fuel such as coal.
Additionally, changing international economic and political conditions may have
a dramatic impact upon crude oil and natural gas prices.  Many of these factors
are beyond the control of Harken.

      Business Risks.  Harken must continually acquire or explore for and
develop new oil and gas reserves to replace those being depleted by production.
Without successful drilling or acquisition ventures, Harken's oil and gas
assets and properties and revenues derived therefrom will decline over time.
To the extent Harken engages in drilling activities, such activities carry the
risk that no commercially viable oil or gas production will be obtained.  The
cost of drilling, completing and operating wells is often uncertain.  Moreover,
drilling may be curtailed, delayed or canceled as a result of many factors,
including shortage of available working capital, title problems, weather
conditions, environmental concern, shortages of or delays in delivery of
equipment, as well as the financial instability of well operators, major
working interest owners and drilling and well servicing companies.  The
availability of a ready market for Harken's oil and gas depends on numerous
factors beyond its control, including the demand for and supply of oil and gas,
the proximity of Harken's reserves to pipelines, the capacity of such
pipelines, fluctuation in seasonal demand, the effects of inclement weather,
and government regulation.  New wells may be shut-in for lack of a market until
a pipeline or gathering system with available capacity is extended into the
area.

      Operating Hazards and Uninsured Risks.  The operations of Harken are
subject to the inherent risks normally associated with exploration for and
production of oil and gas, including blowouts, cratering, pollution and fires,
each of which could result in damage to or destruction of oil and gas wells or
production facilities or damage to persons and property.  As is common in the
oil and gas industry, Harken is not fully insured against these risks, either
because insurance is not available or because Harken has elected to self-insure
due to high premium costs.  The occurrence of a significant event not fully
insured against could have a material adverse effect on Harken's financial
condition.

      Environmental Regulation.  Harken's domestic activities are subject to
various Navajo, federal, state, and local laws and regulations covering the
discharge of material into the environment or otherwise relating to protection
of the environment.  In particular, Harken's oil and gas exploration,
development and production, its activities in connection with storage and
transportation of liquid hydrocarbons and its use of facilities for treating,
processing, recovering, or otherwise handling hydrocarbons and wastes therefrom
are subject to stringent environmental regulation by governmental authorities.
In addition to these domestic laws and regulations, Harken's international
operations are subject to the laws, regulations and governmental approvals of
each foreign country in which it conducts activities including, but not limited
to, environmental laws and regulations governing oil and gas operations.  The
environmental legislation of Colombia provides for restrictions and
prohibitions on spills, releases or emissions of various substances produced in
association with oil operations.  Under Colombia's environmental laws, the
Company is required to submit a report evaluating the environmental impact of
any actions proposed to be taken which might have a negative impact on the
environment for approval to the Colombian Ministry of the Environment.
Specifically, Harken is required to submit environmental impact reports
regarding each well Harken proposes to drill, all seismic activities and any
proposed pipelines or trucking activity.  Failure to timely receive approval of
environmental reports has in the past delayed Harken's operations and there can
be no assurance that Harken will not suffer future delays.  Colombia's
regulatory framework with regard to environmental protection is not as fully
developed and detailed as that which exists in the United States.  The Company
intends that its operations in Colombia will be designed to meet standard
international petroleum industry practice and, as they develop, Colombian
requirements.  Such





                                       8
<PAGE>   10
domestic and foreign laws and regulations have increased the costs of planning,
designing, drilling, installing, operating and abandoning Harken's oil and gas
wells and other facilities and may do so in the future.

      Imprecise Nature of Reserve Estimates.  Reserve estimates are imprecise
and may be expected to change as additional information becomes available.
Furthermore, estimates of oil and gas reserves, of necessity, are projections
based on engineering data, and there are uncertainties inherent in the
interpretation of such data as well as the projection of future rates of
production and the timing of development expenditures.  Reserve engineering is
a subjective process of estimating underground accumulations of oil and gas
that cannot be measured in an exact way, and the accuracy of any reserve
estimate is a function of the quality of available data and of engineering and
geological interpretation and judgment.

      Competition.  The oil and gas industry is competitive in all its phases.
Competition is particularly intense respecting the acquisition of desirable
producing properties and the sale of oil and natural gas production.  Harken's
competitors in oil and gas exploration, development and production include
major oil companies and numerous independent oil and gas companies, and
individual producers and operators.  Many of Harken's competitors possess and
employ financial and personnel resources substantially greater than those which
are available to Harken, and may, therefore, be able to pay greater amounts for
desirable leases and to define, evaluate, bid for and purchase a greater number
of producing prospects than the financial or personnel resources of Harken will
permit.

      Extensive Regulation.  The production of oil and gas is subject to
extensive Navajo, federal and state laws, rules, orders and regulations
governing a wide variety of matters, including the drilling and spacing of
wells, allowable rates of production, prevention of waste and pollution and
protection of the environment.  In addition to these domestic laws and
regulations, Harken's international operations are subject to the laws,
regulations and governmental approvals of each foreign country in which it
conducts activities including, but not limited to, environmental laws and
regulations governing oil and gas operations.  Such laws, rules and regulations
are subject to change.  Any such change in any law, rule or regulation could
have the effect of increasing the Company's cost  of exploration or production
or may limit the Company's revenues by regulating the level of oil and gas
production, either of which could have a material adverse effect on the
financial condition of the Company.

                                USE OF PROCEEDS

      Harken will not receive any part of the proceeds from the sale of Shares
by the Selling Stockholders.





                                       9
<PAGE>   11
                              SELLING STOCKHOLDERS

     This Prospectus covers the offer and sale of the Shares by certain of the
Selling Stockholders.  Set forth below are the names of  the Selling
Stockholders, the nature of any position, office or other material relationship
that the Selling Stockholders have had within the last three years with the
Company or any of its predecessors or affiliates, the number of shares of Common
Stock owned by such Selling Stockholders as of the date of this Prospectus, the
number of shares of Common Stock which may be offered by the Selling
Stockholders pursuant to this Prospectus, and the number of shares of Common
Stock owned by the Selling Stockholders upon completion of the offering if all
of the Shares held by the Selling Stockholders are sold.  Any or all of the
Shares listed below may be offered for sale by the Selling Stockholders from
time to time.

<TABLE>
<CAPTION>
                                                                                               Percent of
                                             Shares                            Shares         Common Stock
                                        Beneficially Owned     Shares    Beneficially Owned   Owned After
                                           Prior to the       Offered         After the            the
         Selling Stockholders                Offering          Hereby        Offering(1)       Offering(1)
--------------------------------------    --------------     -----------    -------------     ------------ 
<S>                                       <C>                <C>               <C>                 <C>
RP&C International (Guernsey) Limited     1,116,002          501,538 (3)       614,464             (5)

The Royal Bank of Scotland Trust             14,620           14,620 (4)          -0-              (5)
Company (Jersey) J331C

David P. Quint                              101,787           91,787 (4)        10,000             (5)

Sir Robert Clark                              6,029            1,829 (4)         4,200             (5)
</TABLE>

___________________


(1)   Assumes no other disposition or acquisition of Common Stock and all
      Shares included herein are sold.

(2)   RP&C International (Guernsey) Limited owns directly 274,015 shares of
      Common Stock. It also beneficially owns an aggregate of 841,987 shares of
      Common Stock that may be acquired pursuant to the exercise of warrants to
      purchase Common Stock and upon the conversion or redemption of the Notes.

(3)   Of the 501,538 shares of Common Stock being offered hereby, 200,000 shares
      relate to Common Stock purchase warrants and 301,538 relate to the Notes. 

(4)   Represents shares of Common Stock which are issuable upon the exercise of
      non-transferrable warrants to purchase Common Stock.

(5)   Less than one percent.

      In May 1998, the Company issued 85,000,000 of its 5% Senior Convertible
Notes due 2003 (the "Notes") pursuant to a Trust Indenture between the Company
and Marine Midland Bank, as Trustee.  The Notes were issued in a transaction
complying with the provision of Regulation S.  The Common Stock which is
issuable upon the conversion of the Notes, or upon the redemption thereof for
shares of Common Stock, will be accomplished in transactions complying with
Regulation S or pursuant to transactions that will be exempt from the
registration provisions of the Act. The shares of Common Stock issuable upon
such conversion or redemption of the Notes may be offered and sold from time to
time by the holders thereof pursuant to this Prospectus. The Registration
Statement of which this Prospectus is a part has been filed with the SEC
pursuant to the Trust Indenture. The number of shares into which the Notes will
be convertible when the Registration Statement is declared effective is
13,669,230.

      The Registration Statement has been filed pursuant to Rule 415 under the
Securities Act to afford the holders of the securities offered hereby the
opportunity to sell such securities in a public transaction rather than
pursuant to an exemption from the registration and prospectus delivery
requirements of the Act.  Because the Notes are in bearer form, the Company
does not know the identities of the holders thereof, and will not know their or
their nominees' identities until such time as certificates representing the
Common Stock are issued.  Accordingly, the Company has not named such holders
herein.





                                       10
<PAGE>   12
     In addition to the sale of the Common Stock issuable upon conversion or
redemption of the Notes, this Prospectus covers the offer and sale by RP&C
International (Guersey) Limited ("RP&C") of 200,000 shares of Common Stock. Such
shares of Common Stock are issuable to RP&C upon exercise of warrants held by
RP&C.  RP&C was a Lead Manager in the offering of the Notes. The warrants were
issued as compensation in connection with the offering. RP&C was also a Lead
Manager in 1996 and 1997, respectively, with respect to the Company's offering
pursuant to Regulation S of its 6.5% Senior Convertible Notes Due 2000 and 5.5%
Senior Convertible Notes Due 2002.  RP&C has not held any position or office
within the Company and has not had any other material relationship with the
Company within the last three years.


                                                                    



                                       11
<PAGE>   13
                              PLAN OF DISTRIBUTION

      The Company will not receive any proceeds from the sale of Common Stock
owned by the Selling Stockholders.  It is anticipated that the Selling
Stockholders will offer the Shares in the manner set forth on the cover page of
this Prospectus, from time to time, directly or through broker-dealers or
underwriters who may act solely as agents or may acquire the Shares as
principals, in all cases as designated by the Selling Stockholders.  Such
underwriters or broker- dealers acting either as principal or as agent, may
receive compensation in the form of usual and customary or specifically
negotiated underwriting discounts, concessions or commissions from the Selling
Stockholders or the purchasers of the securities offered hereby for whom they
may act as agent.

      The net proceeds to the Selling Stockholders from the sale of Common
Stock so offered will be the purchase price of the Common Stock sold less the
aggregate agents' commissions and underwriters' discounts, if any, and other
expenses of issuance and distribution not borne by the Company.  The Selling
Stockholders and any dealers or agents that participate in the distribution of
Common Stock may be deemed to be "underwriters" within the meaning of the
Securities Act.

      At any time a particular offer of Common Stock is made, to the extent
required, the specific shares of Common Stock to be sold, the purchase price,
public offering price, the names of any such agent, dealer or underwriter and
any applicable commission or discount with respect to a particular offering
will be set forth in an accompanying Prospectus Supplement.  Such Prospectus
Supplement may, if necessary, be in the form of a post-effective amendment to
the Registration Statement of which this Prospectus is a part, and will be
filed with the Commission to reflect the disclosure of additional information
with respect to the distribution of such securities.

      The Shares being offered by the Selling Stockholders or their respective
pledgees, donees, transferees or other successors in interest, will be sold in
one or more transactions (which may involve block transactions) on the American
Stock Exchange or on such other market on which the Common Stock may from time
to time be trading, in privately-negotiated transactions, through the writing
of options on the Shares, short sales or any combination thereof.  The sale
price to the public may be the market price prevailing at the time of sale, a
price related to such other price as the Selling Stockholders determine from
time to time.  The Shares may also be sold pursuant to Rule 144.  The Selling
Stockholders shall have the sole and absolute discretion not to accept any
purchase offer or make any sale of Shares if they deem the purchase price to be
unsatisfactory at any particular time.

      The Selling Stockholders or their respective pledgees, donees,
transferees or other successors in interest, may also sell the Shares directly
to market makers in acting as principals and/or broker-dealers acting as agents
for themselves or their customers.  It is possible that a Selling Stockholder
will attempt to sell shares of Common Stock in block transactions to market
makers or other purchasers at a price per share which may be below the then
market price.  There can be no assurance that all or any of the Shares offered
hereby will be issued to, or sold by, the Selling Stockholders.

      The Selling Stockholders, alternatively, may sell all or any part of the
Shares offered hereby through an underwriter.  No Selling Stockholder has
entered into any agreement with a prospective underwriter and there is no
assurance that any such agreement will be entered into.  If a Selling
Stockholder enters into such an agreement or agreements, the relevant details
will be set forth in a supplement or revisions to this Prospectus.

      The Selling Stockholders and any others persons participating in the sale
or distribution of the Shares will be subject to applicable provisions of the
Exchange Act and the rules and regulations thereunder, which provisions may
limit the timing of purchases and sales of any of the Shares by the Selling
Stockholders or any other such person. The foregoing may affect the
marketability of the Shares.

      Pursuant to certain agreements between the Company and Selling
Stockholders, the Company has agreed to file a "shelf" registration statement
pursuant to Rule 415 under the Securities Act covering the sale of shares of
Common Stock held by the Selling Stockholders, and to use its reasonable best
efforts to maintain the effectiveness of any such registration statement for no
less than two years from the date of effectiveness of such





                                       12
<PAGE>   14
registration statement.  In addition, the Company has agreed to bear certain
expenses of registration of the Shares under the federal and state securities
laws (currently estimated to be $30,000).  The Company has also agreed to
indemnify the Selling Stockholders, or their transferees or assigns, against
certain liabilities, including liabilities under the Securities Act, or to
contribute to payments the Selling Stockholders may be required to make in
respect thereof.

      To comply with the securities laws of certain jurisdictions, the
securities offered hereby may be offered or sold in such jurisdictions only
through registered or licensed brokers or dealers.  In addition, in certain
jurisdictions the securities offered hereby may not be offered or sold unless
they have been registered or qualified for sale in such jurisdictions or an
exemption from registration or qualification is available and is complied with.

                                 LEGAL MATTERS

      The validity of the Shares will be passed upon for Harken by Gregory S.
Porter, Esq., Vice President - Legal of Harken.

                                    EXPERTS

      The consolidated financial statements of the Company included in the
Company's Annual Report on Form 10-K for the year ended December 31, 1997,
which is incorporated by reference herein, have been audited by Arthur Andersen
LLP, independent public accountants, as indicated in their report with respect
thereto, and are incorporated by reference herein in reliance upon the
authority of said firm as experts in accounting and auditing in giving said
report.





                                       13
<PAGE>   15
                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

      The expenses to be paid by the Company in connection with the offering
described in this Registration Statement are estimated as follows:

<TABLE>
<S>                                        <C>
Commission Registration Fee . . . . .        $ 20,246.00

Printing and Engraving Expenses . . .           2,000.00

Accounting Fees and Expenses  . . . .           2,000.00
Blue Sky Fees and Expenses  . . . . .           1,000.00

Miscellaneous . . . . . . . . . . . .           4,754.00
                                                ________
                                             -----------
            Total . . . . . . . . . .        $ 30,000.00
                                             ===========
</TABLE>

ITEM 15.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

      Under Section 145 of the General Corporation Law of the State of Delaware
("Delaware Law"), a Delaware corporation may indemnify its directors, officers,
employees and agents against expenses (including attorneys fees), judgments,
fines and settlements in nonderivative suits, actually and reasonably incurred
by them in connection with the defense of any action, suit or proceeding in
which they or any of them were or are made parties or are threatened to be made
parties by reason of their serving or having served in such capacity.  Delaware
law, however provides that such person must have acted in good faith and in a
manner they reasonably believed to be in or not opposed to the best interests
of the corporation, and in the case of a criminal action, such person must have
had no reasonable cause to believe his or her conduct was unlawful. Section 145
further provides that in connection with the defense or settlement of any
action by or in the right of the corporation, a Delaware corporation may
indemnify its directors and officers against expenses actually and reasonably
incurred by them if, in connection with the matters in issue, they acted in
good faith, in a manner they reasonably believed to be in or not opposed to the
best interests of the corporation, except that no indemnification may be made
with respect to any claim, issue or matter as to which such person has been
adjudged liable for negligence or misconduct unless the Court of Chancery or
the court in which such action or suit is brought approves such
indemnification.  Section 145 further permits a Delaware corporation to grant
its directors and officers additional rights of indemnification through bylaw
provisions and otherwise, and to purchase indemnity insurance on behalf of its
directors and officers.  Indemnification is mandatory to the extent a claim,
issue or matter has been successfully defended.

      Article Ten of the Company's Certificate of Incorporation and Article VII
of the Company's bylaws provide, in general, that the Company shall indemnify
its directors and officers under certain of the circumstances defined in
Section 145.  The Company has entered into agreements with each member of its
Board of Directors pursuant to which it will advance to each director costs of
litigation in accordance with the indemnification provisions of the Company's
Certificate of Incorporation and bylaws.





                                      II-1
<PAGE>   16
ITEM 16.  EXHIBITS.

<TABLE>
      <S>          <C>
        4.1  -     Form of certificate representing shares of Common Stock (filed as Exhibit 1 to Harken's Registration
                   Statement on Form 8-A, File No. 0-9207, and incorporated by reference herein).
        4.2  -     Rights Plan dated as of April 6, 1998, by and between Harken Energy Corporation and ChaseMellon
                   Shareholder Services L.L.C. (filed as Exhibit 4 to Harken's Current Report on Form 8-K dated April 7,
                   1998, file No. 0-9207, and incorporated by reference herein).
        4.3  -     Certificate of Designations of Series E Junior Participating Preferred Stock (filed as Exhibit B to
                   Exhibit 4 to Harken's Current Report on Form 8-K dated April 7, 1998, file No. 0-9207, and
                   incorporated by reference herein).
        4.4  -     Certificate of Designations, Preferences and Rights of Series F Convertible Preferred Stock (filed as
                   Exhibit 4.8 to Harken's Quarterly Report on Form 10-Q  for the quarterly period ended March 31, 1998,
                   file No. 0-9207, and incorporated by reference herein).
      * 5.1  -     Opinion of Gregory S. Porter, Esq.
      *23.1  -     Consent of Arthur Andersen LLP.
      *23.2  -     Consent of Gregory S. Porter, Esq. (included in opinion filed as Exhibit 5.1).
      *24.1  -     Powers of Attorney.
</TABLE>

__________________________
* Filed herewith.


ITEM 17.  UNDERTAKINGS.

      (a)    The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
Registrant's Annual Report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in the Registration Statement shall be deemed to be a
new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

      (b)    The undersigned Registrant hereby undertakes:

             (1)   To file, during any period in which offers or sales are
being made, a post-effective amendment to this Registration Statement:

                          (i)   To include any prospectus required by Section
                                10(a)(3) of the Securities Act;

                          (ii)  To reflect in the prospectus any facts or
                                events arising after the effective date of the
                                Registration Statement (or the most recent
                                post-effective amendment thereto) which,
                                individually or in the aggregate, represent a
                                fundamental change in the information set forth
                                in the Registration Statement.  Notwithstanding
                                the foregoing, any increase or decrease in
                                volume of securities offered (if the total
                                dollar value of securities offered would not
                                exceed that which was registered) and any
                                deviation from the low or high end of the
                                estimated maximum offering range may be
                                reflected in the form of prospectus filed with
                                the Commission pursuant to Rule 424(b) if, in
                                the aggregate, the changes in volume and price
                                represent no more than a 20% change in the
                                maximum aggregate offering price set forth in
                                the "Calculation of Registration Fee" table in
                                the effective Registration Statement;

                          (iii) To include any material information with
                                respect to the plan of distribution not
                                previously disclosed in the Registration
                                Statement or any material change to such
                                information in the Registration Statement;





                                      II-2
<PAGE>   17
provided, however, that paragraphs (i) and (ii) above do not apply if the
registration statement is on Form S-3 or Form S-8, and the information required
to be included in a post-effective amendment by those paragraphs is contained
in periodic reports filed by the Registrant pursuant to Section 13 or Section
15(d) of the Exchange Act that are incorporated by reference in the
Registration Statement.

             (2)   That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

             (3)   To remove from registration by means of a post-effective
amendment any of the securities being registered which remain unsold at the
termination of the offering.

      (c)    Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the provisions described under Item 15 above, or
otherwise, the Registrant has been advised that, in the opinion of the
Commission, such indemnification is against public policy as expressed in the
Securities Act and is, therefore, unenforceable.  In the event that a claim for
indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.





                                      II-3
<PAGE>   18
                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-3 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Irving, State of Texas, on June 26, 1998.

                                       HARKEN ENERGY CORPORATION
                                       
                                       
                                                *                             
                                       ----------------------------------------
                                       Mikel D. Faulkner, Chairman of the 
                                       Board and Chief Executive Officer


      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>
          Signature                                  Title                              Date
          ---------                                  -----                              ----  
<S>                                 <C>                                             <C>
               *                     Chairman of the Board and Chief                 June 26, 1998
 ---------------------------         Executive Officer (Principal                       
 Mikel D. Faulkner                   Executive Officer)                   
                                                                          




              *                      Vice Chairman and Director                      June 26, 1998
 -------------------------------                                                                     
 Richard H. Schroeder



              *                      President and Chief Operating                   June 26, 1998
 ---------------------------         Officer and Director                                        
 Bruce N. Huff                                           



              *                      President of Harken International,              June 26, 1998
 ---------------------------         Ltd. and Director                                            
 Stephen C. Voss                                      



              *                      Director                                        June 26, 1998
 ---------------------------                                                                     
 Gary R. Petersen




              *                      Director                                        June 26, 1998
 -------------------------------                                                                     
 Michael M. Ameen, Jr.
</TABLE>





                                      II-4
<PAGE>   19


<TABLE>
<S>                                  <C>                                            <C>
                                     Director                                       June 26, 1998
 -------------------------------                                                                     
 Michael R. Eisenson




              *                      Director                                       June 26, 1998
 ---------------------------                                                                     
 Hobart A. Smith



             *                       Director                                       June 26, 1998
 ---------------------------                                                                     
 Donald W. Raymond




              *                      Director                                       June 26, 1998
 -------------------------------                                                                     
 Gary B. Wood




               *                     Vice President of Finance and Chief            June 26, 1998
 --------------------------------    Financial Officer (Principal                                     
 A. Wayne Hennecke                   Accounting Officer and Principal
                                     Financial Officer               
                                                                     
</TABLE>

*Larry E. Cummings, by signing his name hereto, does hereby sign this
Registration Statement on behalf of Harken Energy Corporation and each of the
above-named officers and directors of such Company pursuant to powers of
attorney, executed on behalf of the Company and each officer and director.

/s/ Larry E. Cummings         
-------------------------------- 
Larry E. Cummings,
Attorney-in-Fact





                                      II-5
<PAGE>   20
                               INDEX TO EXHIBITS

<TABLE>
<CAPTION>
                                                                                              Sequentially
   Exhibit No.                                    Exhibit                                     Numbered Page
   -----------          ------------------------------------------------------------          -------------                         
      <S>               <C>
        4.1             Form of  certificate  representing shares  of Harken  common
                        stock, par  value  $.01 per  share (filed  as  Exhibit 1  to
                        Harken's Registration  Statement on  Form 8-A,  File No.  0-
                        9207, and incorporated by reference herein).

        4.2             Rights Plan  dated  as of  April  6, 1998,  by  and  between
                        Harken   Energy  Corporation  and   ChaseMellon  Shareholder
                        Services  L.L.C. (filed  as Exhibit  4  to Harken's  Current
                        Report  on Form 8-K  dated April  7, 1998, file  No. 0-9207,
                        and incorporated by reference herein).

        4.3             Certificate   of   Designations    of   Series   E    Junior
                        Participating  Preferred  Stock  (filed  as  Exhibit   B  to
                        Exhibit 4  to  Harken's Current  Report  on Form  8-K  dated
                        April  7,  1998,  file  No.   0-9207,  and  incorporated  by
                        reference herein).

        4.4             Certificate  of  Designations,  Preferences  and  Rights  of
                        Series F Convertible  Preferred Stock (filed as  Exhibit 4.8
                        to  Harken's  Quarterly  Report  on   Form  10-Q    for  the
                        quarterly period ended March 31, 1998, file  No. 0-9207, and
                        incorporated by reference herein).

       *5.1             Opinion of Gregory S. Porter, Esq.

      *23.1             Consent of Arthur Andersen LLP.

      *23.2             Consent  of Gregory  S. Porter,  Esq.  (included in  opinion
                        filed as Exhibit 5.1).

      *24.1             Powers of Attorney.
</TABLE>


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* Filed herewith