UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934


        Date of Report (Date of earliest event reported):  April 12, 2005


                             PENN OCTANE CORPORATION
             (Exact name of registrant as specified in its charter)


     Delaware                    000-24394               52-1790357
     (State of                   (Commission             (IRS Employer
     Incorporation)              File Number)            Identification No.)


     77-530 Enfield Lane, Bldg D
     Palm Desert, California                             92211
     (Address of principal executive offices)            (Zip Code)

                                 (760) 772-9080
              (Registrant's telephone number, including area code)

                                       N/A
          (Former Name or Former Address, if Changed Since Last Report)


     Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

     [ ]  Written communications pursuant to Rule 425 under the Securities Act
(17 CFR 230.425)

     [ ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17
CFR 240.14a-12)

     [ ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
Exchange Act (17 CFR 240.14d-2(b))

     [ ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
Exchange Act (17 CFR 240.13e-4(c))


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ITEM 2.02.  RESULTS OF OPERATIONS AND FINANCIAL CONDITION

     On  February  22,  2005,  Penn  Octane  Corporation  ("Penn  Octane"),  in
connection  with  the change in its fiscal year end from July 31 to December 31,
filed  with  the  Securities and Exchange Commission a Transition Report on Form
10-Q  (the "Penn Octane Form 10-Q") for the period August 1 - December 31, 2004,
in  lieu  of an Annual Report on Form 10-K.  On April 12, 2005, Rio Vista Energy
Partners  L.P.  ("Rio  Vista"),  a  consolidated  subsidiary  of Penn Octane for
financial accounting purposes, filed with the Securities and Exchange Commission
Rio  Vista's  Annual  Report on Form 10-K for the fiscal year ended December 31,
2004 (the "Rio Vista Form 10-K"), including audited financial statements for the
fiscal  year ended December 31, 2004.  Due to the different filing deadlines and
information  requirements  of  the  two  forms, the Rio Vista Form 10-K contains
certain  disclosures  concerning  events  during  the  period  February 22, 2005
through  March  31, 2005 and other information (including information about Penn
Octane)  not  included  in  the Penn Octane Form 10-Q or other report previously
filed  by  Penn  Octane.

     A copy of the Rio Vista Form 10-K is attached as an exhibit.

ITEM 9.01.   FINANCIAL STATEMENTS AND EXHIBITS

     (c)  Exhibits

          99.1      Rio Vista Energy Partners L.P. Annual Report on Form 10-K


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                                   SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                   PENN OCTANE CORPORATION


                                   By:   /s/ Ian T. Bothwell
                                      ------------------------------------------
                                   Name:  Ian T. Bothwell
                                   Title:  Vice President,
                                           Chief Financial Officer, Treasurer,
                                           and Assistant Secretary, (Principal
                                           Financial and Accounting Officer)

Date:  April 12, 2005


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                                  EXHIBIT INDEX


Exhibit No.    Description                                              Page No.
- -----------    -----------                                              --------

   99.1        Rio Vista Energy Partners Annual Report on Form 10-K        5


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