Filed by Unit Corporation
                       Pursuant to Rule 425 under the Securities Act of 1933 and
  Deemed Filed Pursuant to Rule 14a-12 under the Securities Exchange Act of 1934

                                        Subject Company: PETROCORP INCORPORATION
                                                     Commission File No. 0-22650

                                                             Dated: July 1, 2003





           1000 Kensington Tower, 7130 South Lewis Avenue, Tulsa, Oklahoma 74136
                                        Telephone 918 493-7700, Fax 918 493-7714


                               Contact:     Larry D. Pinkston
                                            Executive Vice President, Treasurer
                                              and Chief Financial Officer
                                            (918) 493-7700

For Immediate Release...
July 1, 2003

                        UNIT CORPORATION ANNOUNCES INTENT
                        TO ACQUIRE PETROCORP INCORPORATED

     Tulsa, Oklahoma . . . Unit Corporation (NYSE - UNT) announced today that it
has signed a letter of intent with PetroCorp Incorporated (AMEX - PEX) to
acquire all outstanding shares of PetroCorp for approximately $190,000,000. The
acquisition price is to be paid using a combination of 2,000,000 shares of Unit
Corporation stock and cash.
     PetroCorp, a Tulsa-based company, explores and develops oil and natural gas
properties primarily in Texas and Oklahoma. Allocation of the purchase price is
approximately $101 million to working capital, $78 million to proved reserves
and the remaining $11 million to undeveloped leasehold and partnership interest.
     Consummation of the transaction is subject to several conditions typical of
transactions such as this. It is anticipated that the transaction will be
immediately accretive to earnings and cash flow per share.
     John G. Nikkel, Chief Executive Officer of Unit Corporation said, "The
acquisition fits Unit's mission of creating value for our shareholders on a per
share basis."

                                INVESTOR NOTICES

     This press release includes "forward-looking statements" as defined by the
Securities and Exchange Commission. Such statements are those about the
companies' merger and strategic plans, expectations and objectives for future
operations. All statements, other than statements of historical facts, included
in this press release that address activities, events or developments the
companies expect, believe or anticipate will or may occur in the future are
forward-looking statements. This includes completion of


the proposed merger, future financial performance, future equity issuance
and other matters. These statements are based on certain assumptions made by
Unit based on its experience and opinion of historical trends, current
conditions, expected developments and other causes it believes are proper in the
circumstances. Such statements are subject to several assumptions, risks and
uncertainties, many of which are beyond the control of Unit. Investors are
cautioned that any such statements are not guarantees of future performance and
actual results or developments may differ materially from those projected in the
forward-looking statements.

     In the event a definitive agreement is reached, investors and security
holders are advised to read the joint proxy statement/ prospectus that will be
included in the Registration Statement on Form S-4 to be filed with the SEC in
connection with the proposed merger because it will contain important
information. The joint proxy statement/prospectus will be filed with the SEC by
Unit and PetroCorp Incorporated. Investors and security holders may get a free
copy of the joint proxy statement/ prospectus (when available) and other
documents filed by Unit and PetroCorp Incorporated with the SEC at the SEC's web
site at www.sec.gov. The joint proxy statement/prospectus and such other
documents (about Unit) may also be obtained free from Unit by directing such
request to: Unit Corporation, 1000 Kensington Tower I, 7130 S. Lewis, Tulsa, OK
74136, Attention: Investor Relations, telephone: (918) 493-7700, e-mail:
linda.swanson@unitcorp.com.

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     Unit Corporation is a Tulsa-based, publicly held energy company engaged
through its subsidiaries in oil and gas exploration, production and contract
drilling. Unit's Common Stock is listed on the New York Stock Exchange under the
symbol UNT. For more information about Unit Corporation, visit our website at
http://www.unitcorp.com.