Exhibit 8.1
    
 
             [Skadden, Arps, Slate, Meagher & Flom LLP letterhead]
 
   
                                             November 10, 1997
    
 
Peter Kiewit Sons' Inc.
1000 Kiewit Plaza
Omaha, NE 68131
 
Dear Ladies and Gentlemen:
 
    We are acting as special tax counsel to Peter Kiewit Sons' Inc., a Delaware
corporation ("PKS"), in connection with filing with the United States Securities
and Exchange Commission (the "Commission") of the Registration Statement on Form
S-4 (the "Registration Statement") of PKS and PKS Holdings, Inc., a newly
formed, direct, wholly owned subsidiary of PKS ("PKS Holdings"), relating to the
proposed distribution of Class R Convertible Common Stock of PKS and the
proposed splitoff of PKS Holdings.
 
   
    We hereby confirm, that the discussion set forth under the heading "THE
TRANSACTION-- Material U.S. Federal Income Tax Considerations--Tax Treatment of
Class R Stock" in the Proxy Statement/Joint Prospectus (the "Proxy
Statement/Prospectus") included within the Registration Statement reflects our
opinion other than with respect to the matters of fact referred to therein.
    
 
    This opinion is limited to federal law of the United States and
administrative rulings of the Internal Revenue Service as in effect on the date
hereof. We have no obligation to advise you or any other person of changes in
law or in the administrative rulings of the Internal Revenue Service that occur
after the date hereof.
 
   
    This opinion is furnished to you solely for your benefit in connection with
the filing of the Registration Statement and, except as set forth below, is not
to be used, circulated, quoted or otherwise referred to for any purpose without
our prior written consent. We consent to the use of our name in the Proxy
Statement/ Prospectus and to the filing of this opinion with the Commission as
an exhibit to the Registration Statement. In giving this consent, we do not
thereby admit that we are within the category of persons whose consent is
required under Section 7 of the Securities Act of 1933, as amended, or the rules
and regulations of the Commission promulgated thereunder.
    
 
                                          Very truly yours,
                                          /s/ Skadden, Arps, Slate,
                                           Meagher & Flom LLP