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                                                                       Exhibit 5

                         (Riordan & McKinzie Letterhead)

                                  July 6, 1998

Superior National Insurance Group, Inc.
26601 Agoura Road
Calabasas, CA 91302

Ladies and Gentlemen:

         We have acted as counsel to Superior National Insurance Group, Inc., a
Delaware corporation (the "Company"), in connection with the registration under
the Securities Act of 1933, as amended, of the issuance and sale of 6,548,664
shares of the Company's common stock, par value $.01 per share (the "Common
Stock"), and 6,548,664 transferable subscription rights to purchase shares of
Common Stock (the "Rights"), pursuant to a Registration Statement on Form S-1
(Registration No. 333-_________), including the prospectus and all amendments,
exhibits and documents related thereto (collectively, the "Registration
Statement"), in accordance with the terms of the Registration Statement.

         Based upon our examination of the originals or copies of such
documents, corporate records, certificates of officers of the Company and other
instruments as we have deemed necessary and upon the laws as presently in
effect, we are of the opinion that (i) the Common Stock has been duly authorized
for issuance by the Company and, upon issuance, delivery and subscription and
payment in accordance with the terms of the Registration Statement, the Common
Stock will be validly issued, fully paid and nonassessable and (ii) the Rights
have been duly authorized for issuance by the Company and, upon issuance and
delivery in accordance with the terms of the Registration Statement, will be
legal, valid and binding obligations of the Company, subject to the effect of
applicable bankruptcy, insolvency, reorganization, moratorium and other laws
relating to, or affecting, creditors' rights and remedies generally and general
principles of equity (regardless of whether considered in a proceeding at law or
in equity.)

         We hereby consent to the incorporation by reference of this opinion as
an exhibit to the Registration Statement. We also consent to the reference to
Riordan & McKinzie under the caption "Legal Matters" in the Registration
Statement.

                                        Very truly yours,



                                        /s/ Riordan & McKinzie