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                                    EXHIBIT 5


           [LETTERHEAD OF RICHMAN, MANN, CHIZEVER, PHILLIPS & DUBOFF.]


                               September 19, 2000


Penn Octane Corporation
77-530 Enfield Lane, Building D
Palm Desert, California 92211

        Re:    Registration Statement on Form S-3

Gentlemen:

        We have acted as securities counsel to Penn Octane Corporation, a
Delaware corporation (the "Company"), in connection with the preparation and
filing with the Securities and Exchange Commission under the Securities Act of
1933, as amended (the "Securities Act"), of a Registration Statement on Form S-3
(the "Registration Statement"). The Registration Statement relates to the public
offering by certain selling stockholders named therein (the "Selling
Stockholders") of up to 7,357,111 shares of common stock of the Company (the
"Shares").

        The Shares are to be sold by the Selling Stockholders. This opinion is
being furnished in accordance with the requirements of Item 601(b)(5) of
Regulation S-K under the Securities Act.

        In connection with this opinion, we have examined and are familiar with
originals or copies, certified or otherwise identified to our satisfaction, of
such documents, corporate records and other instruments as we have deemed
necessary or appropriate as a basis for the opinions set forth herein, including
(i) the Registration Statement of the Company filed with the Securities and
Exchange Commission; (ii) the Certificate of Incorporation and the Bylaws of the
Company; (iii) the form of common stock Certificate; (v) copies of certain
resolutions adopted by the Board of Directors of the Company relating to the
filing of the Registration Statement and any amendments of supplements thereto
and related matters made available to us by the Corporation for inspection; and
(vi) such other documents as we have deemed necessary or appropriate as a basis
for the opinions set forth below.

        In our examination, we have assumed the genuineness of all signatures,
the legal capacity of all natural persons, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified or photostatic copies and the
authenticity of the originals of such latter documents. In making our
examination of documents executed by parties other than the Company, we have
assumed that such parties had the power, corporate or other, to enter into and
perform all obligations thereunder and have also assumed the due authorization
by all requisite action, corporate or other, and execution and delivery by such
parties of such documents and the validity and binding effect thereof. As to any
facts material to the opinions expressed herein which were not independently
established or verified, we have relied upon oral or written statements and
representations of officers and other representatives of the Company and others.

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        We express no opinion as to compliance with the securities or "blue sky"
laws of any state in which the common stock are proposed to be offered and sold
or as to the effect, if any, which non-compliance with such laws might have on
the validity of issuance of such securities.

        Based on the foregoing, it is our opinion that, subject to effectiveness
with the Securities and Exchange Commission of the Registration Statement and to
registration or qualification under the securities laws of the states in which
securities may be sold, the Shares are duly and validly authorized and
constitute legally issued, fully paid and nonassessable shares of common stock
of the Company.

        We consent to the use of our name under the caption "Legal Matters" in
the Registration Statement, and to the filing of this opinion as an exhibit to
the Registration Statement. By giving you this opinion and consent, we do not
admit that we are experts with respect to any part of the Registration Statement
within the meaning of the term "expert" as used in Section 11 of the Securities
Act or the rules and regulations promulgated thereunder, nor do we admit that we
are in the category of persons whose consent is required under Section 7 of the
Securities Act.

        The opinions set forth herein are based upon the federal laws of the
United States of America and the laws of the State of Delaware, all as now in
effect. We express no opinion as to whether the laws of any particular
jurisdiction apply, and no opinion to the extent that the laws of any
jurisdiction other than those identified above are applicable to the subject
matter hereof. The information set forth herein is as of the date of this
letter. We disclaim any undertaking to advise you of changes which may be
brought to our attention after the effective date of the Registration Statement.

                             Respectfully submitted,

                 /s/ RICHMAN, MANN, CHIZEVER, PHILLIPS & DUBOFF