<PAGE>
Filed pursuant to Rule 424(b)(3)
Registration Number 333-65939
PROSPECTUS SUPPLEMENT
(TO PROSPECTUS DATED OCTOBER 21, 1998)
[PLAINS RESOURCES INC. LOGO]
PLAINS RESOURCES INC.
--------------
BACKGROUND
Pursuant to an exchange offer by Plains Resources Inc., a Delaware
corporation (referred to in this prospectus as "we," "us" and "our"), effective
February 1, 2000, we issued 177,625.505 shares of our Series G preferred stock
in exchange for 177,625.505 shares of our Series E preferred stock. In
connection with the exchange offer, we agreed to extend to the holders of our
Series G preferred stock the same registration rights that such holders had
enjoyed as holders of our Series E preferred stock. This prospectus supplement
extends such rights to the holders of our Series G preferred stock by
supplementing the prospectus dated October 21, 1998 to cover the shares of
common stock that we may issue in the future upon the conversion of shares of
our Series G preferred stock.
SUPPLEMENT
We hereby supplement the prospectus dated October 21, 1998 so that the
selling stockholders are the holders of our Series G preferred stock. Our
prospectus dated October 21, 1998 is hereby supplemented to cover the shares of
common stock that may be issued in the future upon conversion of our Series G
preferred stock.
---------------
MARCH 28, 2000
