EXHIBIT 5.1

Opinion of Frederic Dorwart, Lawyers

                                 June 6, 2001


PetroCorp Incorporated
6733 South Yale
Tulsa, Oklahoma 74136

   Re: Registration Statement on Form S-4

Ladies and Gentlemen:

   We have examined the Registration Statement on Form S-8 to be filed by you
with the Securities and Exchange Commission in connection with the registration
under the Securities Act of 1933, as amended, of 330,393 shares of your common
stock. As your counsel in connection with these transactions, we have examined
the proceedings taken and proposed to be taken in connection with the issue in
sale of the shares.

   It is our opinion that the shares, when issued as described in the
Registration Statement, will be legally and validly issued, fully paid, and non-
assessable.

   We consent to the use of this opinion as an exhibit to the Registration
Statement, including the prospectus constituting a part thereof and any
amendment thereto.


                                        Sincerely,

                                        /s/ FREDERIC DORWART
                                        ---------------------------------
                                        Frederic Dorwart