QuickLinks -- Click here to rapidly navigate through this document

As filed with the Securities and Exchange Commission on March 25, 2003

Registration No. 333 - 35005



SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549


Post-Effective Amendment No. 1
to
FORM S-8
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933


Primus Telecommunications Group, Incorporated
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of
incorporation or organization)
  54-1708481
(I.R.S. Employer Identification No.)

1700 Old Meadow Road
Suite 300
McLean, Virginia 22102
(703) 902-2800

(Address, including zip code, and telephone number, including
area code, of registrant's principal executive offices)

Primus Telecommunications Group, Incorporated 401(k) Plan
(Full Title of the Plan)

K. PAUL SINGH
CHAIRMAN, PRESIDENT AND CHIEF EXECUTIVE OFFICER
PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

1700 Old Meadow Road
Suite 300
McLean, Virginia 22102
(703) 902-2800

(Name, address, including zip code, and telephone number, including area code, of agent for service)


Copies to:
BRIAN J. LYNCH, ESQ.
COOLEY GODWARD LLP

One Freedom Square
11951 Freedom Drive
Reston, Virginia 20190
Tel: (703) 456-8000
Fax: (703) 456-8100






DEREGISTRATION OF SECURITIES

        On September 5, 1997, Primus Telecommunications Group, Incorporated (the "Registrant") filed a registration statement on Form S-8 (No. 333-35005) (the "Registration Statement"), which registered among other things the issuance of 75,000 shares (the "401(k) Plan Shares") of the Registrant's common stock, par value $.01 per share, to be sold pursuant to the Primus Telecommunications Group, Incorporated 401(k) Plan (the "Plan"). Pursuant to General Instruction F to Form S-8 and Rule 416(c) under the Securities Act of 1933, as amended (the "Act"), the Registration Statement was also deemed to register an indeterminate number of interests in the Plan ("Plan Interests") as separate securities required to be registered under Act. The Registrant has terminated the offering of the 401(k) Plan Shares and the Plan Interests. Accordingly, pursuant to the undertaking contained in the Registration Statement, the Registrant is filing this Post-Effective Amendment No. 1 to deregister the Plan Shares and Plan Interests registered pursuant to the Registration Statement that remain unsold as of the date this Post-Effective Amendment No. 1 is filed.



SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Post-Effective Amendment No. 1 to the Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the Town of McLean, County of Fairfax, Commonwealth of Virginia, on the 26th day of March, 2003.


 

 

By:

/s/  
K. PAUL SINGH      
K. Paul Singh
Chairman of the Board, President and Chief
Executive Officer

        Pursuant to the requirements of the Securities Act of 1933, as amended, this Post-Effective Amendment No. 1 to the Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

Name
  Title
  Date
/s/  K. PAUL SINGH      
K. Paul Singh
  Chairman, President,
Chief Executive Officer and Director
(Principal Executive Officer)
  March 26, 2003

/s/  
JOHN F. DEPODESTA*      
John F. DePodesta

 

Executive Vice President and
Director

 

March 26, 2003

/s/  
NEIL L. HAZARD*      
Neil L. Hazard

 

Executive Vice President, Chief
Operating Officer and Chief Financial Officer
(Principal Financial Officer)

 

March 26, 2003

/s/  
TRACY R. BOOK      
Tracy R. Book

 

Vice President and Corporate Controller
(Principal Accounting Officer)

 

March 26, 2003

/s/  
NICK EARLE      
Nick Earle

 

Director

 

March 26, 2003

/s/  
DAVID E. HERSHBERG*      
David E. Hershberg

 

Director

 

March 26, 2003

/s/  
DOUGLAS M. KARP      
Douglas M. Karp

 

Director

 

March 26, 2003

/s/  
JOHN PUENTE *      
John Puente

 

Director

 

March 26, 2003

/s/  
PRADMAN KAUL      
Pradman Kaul

 

Director

 

March 26, 2003

/s/  
PAUL G. PIZZANI      
Paul G. Pizzani

 

Director

 

March 26, 2003

*By:

 

/s/  
K. PAUL SINGH      
K. Paul Singh
Attorney-in-Fact

 

 

 

 



QuickLinks

DEREGISTRATION OF SECURITIES
SIGNATURES