|Exhibit 32.1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
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|CERTIFICATION PURSUANT TO 
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
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|The certification set forth below is being submitted in connection with the filing of the Quarterly Report of Peter Kiewit Sons, Inc. (the Company) on Form 10-Q, for the period ended June 30, 2007, with the Securities and Exchange Commission (the Report), for the purpose of complying with Rule 13a-14(b) or Rule 15d-14(b) of the Securities Exchange Act of 1934 and Section 1350 of Chapter 63 of Title 18 of the United States Code.  The undersigned, Bruce E. Grewcock, Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that:
|(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
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|August 8, 2007                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
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|/s/  Bruce E. Grewcock                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Bruce E. Grewcock
Chief Executive Officer