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                                                                    EXHIBIT 5.1
                                [H&B Letterhead]

September 8, 1999


Venus Exploration, Inc.
1250 N.E. Loop 410
Suite 100
San Antonio, Texas 75209

Re:       Registration Statement on Form S-3 of 11,233,333 shares of Common
          Stock, par value $.01 per share, of Venus Exploration, Inc. ("Common
          Stock")

Gentlemen:

We are securities counsel to Venus Exploration, Inc., a Delaware corporation
(the "Company"), in connection with the registration and issuance of up to
11,233,333 shares of Common Stock (the "Shares"), plus an indeterminate number
of additional shares of Common Stock issuable to prevent dilution resulting
from stock splits, stock dividends or similar events to be sold by the Selling
Stockholders named in the Prospectus constituting a part of this Registration
Statement (the "Selling Stockholders"), in some instances following the
exercise of that certain convertible note (the "Note") described in the
Prospectus or issued in lieu of cash interest payments due on the Note as
described in the Prospectus.

We have examined such documents, records and matters of law as we have deemed
necessary for purposes of this opinion. Based on the foregoing, we are of the
opinion that the Shares are duly authorized and are, or when issued to the
Selling Stockholders in accordance with the terms of the Note described in the
Prospectus contained in the Company's Registration Statement on Form S-3 to
which this opinion is an exhibit will be, validly issued, fully paid and
nonassessable.

In rendering the foregoing opinion, we have relied as to certain factual
matters upon certificates of officers of the Company, the Selling Stockholders
and public officials, and we have not independently checked or verified the
accuracy of the statements contained therein.

We hereby consent to the filing of this opinion as Exhibit 5.1 to this
Registration Statement on Form S-3 filed by the Company to effect registration
of the Shares under the Securities Act of 1933, as amended, and to the
reference to us under the caption "Legal Matters" in the Prospectus
constituting a part of such Registration Statement.

Very truly yours

/s/ Haynes and Boone, LLP