EXHIBIT 5.1


                                 June 10, 1998


Primus Telecommunications Group, Incorporated
1700 Old Meadow Road
McLean, VA 22102

          Re:  Registration Statement on Form S-8
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Ladies and Gentlemen:

          We have acted as special counsel to Primus Telecommunications Group,
Incorporated, a Delaware corporation (the "Company"), in connection with the
preparation and filing with the Securities and Exchange Commission (the
"Commission") of a registration statement (the "Registration Statement") of the
Company on Form S-8 under the Securities Act of 1933, as amended (the "Act"),
relating to shares of common stock, par value $.01 per share, of the Company
(the "Common Stock") which may be issued pursuant to the Primus
Telecommunications Group, Incorporated-TresCom International Stock Option Plan
(the "Plan"), as more fully described in the Registration Statement.

          In this connection, we have examined the Registration Statement,
including the exhibits thereto, the originals or copies, certified or otherwise
identified to our satisfaction, of the Amended and Restated Articles of
Incorporation of the Company, the By-Laws of the Company as amended to date, and
such other documents and corporate records relating to the Company as we have
deemed appropriate for the purpose of rendering the opinion expressed herein.
We express no opinion concerning the laws of any jurisdiction other than the
federal law of the United States and the Delaware General Corporation Law.

 
          In all examinations of documents, instruments and other papers, we
have assumed the genuineness of all signatures on original and certified
documents and the conformity with original and certified documents of all copies
submitted to us as conformed, photostatic or other copies. As to matters of fact
which have not been independently established, we have relied upon
representations of officers of the Company.

          On the basis of the foregoing, we are of the opinion that the Common
Stock when issued pursuant to and in accordance with the Plan, will be legally
issued, fully paid and non-assessable.

          We hereby consent to the filing of a copy of this opinion with the
Securities and Exchange Commission as an exhibit to the Form S-8 Registration
Statement of the Company relating to issuance of the Shares and to the reference
of this firm under the caption "Interests of Named Experts and Counsel" in such
Registration Statement.  However, we do not admit that we come within the
categories of persons whose consent is required under Section 7 of the Act or
the rules and regulations of the Commission promulgated thereunder.


                                 Very truly yours,



                                 /s/ PEPPER HAMILTON LLP