UNITED STATES
                        SECURITIES EXCHANGE COMMISSION
                            Washington, D.C. 20549

- ------------------------------------------------------------------------------


                                 SCHEDULE 13G

                   Under the Securities Exchange Act of 1934
                               (Amendment No. )

                 PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED
                 ---------------------------------------------
                               (Name of Issuer)


                   Common Stock, par value $0.01 per share
                   ---------------------------------------
                        (Title of Class of Securities)


                                  741929103
                             --------------------
                                (CUSIP Number)


                               August 10, 2006
                            -----------------------
            (Date of Event which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

                              [ ]    Rule 13d-1(b)

                              [X]    Rule 13d-1(c)

                              [ ]    Rule 13d-1(d)

* The  remainder  of this  cover  page  shall be  filled  out for a  reporting
person's  initial  filing on this form with  respect to the  subject  class of
securities,  and for any subsequent  amendment  containing  information  which
would alter the disclosures provided in a prior cover page.

The  information  required  in the  remainder  of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities  Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however,  see
the Notes).


                         Continued on following pages
                               Page 1 of 9 Pages
                             Exhibit Index: Page 8





                                 SCHEDULE 13G

CUSIP No.: 741929103                                         Page 2 of 9 Pages

...............................................................................
1.      Names of Reporting Persons.

        I.R.S. Identification Nos. of above persons (entities only).



        KINGDON CAPITAL MANAGEMENT, LLC
...............................................................................

2.      Check the Appropriate Box if a Member of a Group

        (a) [  ]

        (b) [  ]
...............................................................................

3.      SEC Use Only
...............................................................................

4.      Citizenship or Place of Organization

        Delaware
...............................................................................

Number of               5.      Sole Voting Power                5,690,977
Shares                ........................................................
Beneficially
Owned                   6.      Shared Voting Power              0
by Each             ........................................................
Reporting
Person                  7.      Sole Dispositive Power           5,690,977
With                  ........................................................

                        8.      Shared Dispositive Power         0
...............................................................................

9.      Aggregate Amount Beneficially Owned by Each Reporting Person

        5,690,977
...............................................................................

10.     Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
        Instructions)

        [  ]
...............................................................................

11.     Percent of Class Represented by Amount in Row (9)

        5.0%
...............................................................................

12.     Type of Reporting Person:

        OO; IA





                                 SCHEDULE 13G

CUSIP No.: 741929103                                         Page 3 of 9 Pages

...............................................................................
1.      Names of Reporting Persons.

        I.R.S. Identification Nos. of above persons (entities only).



        MARK KINGDON
...............................................................................

2.      Check the Appropriate Box if a Member of a Group

        (a) [  ]

        (b) [  ]
...............................................................................

3.      SEC Use Only
...............................................................................

4.       Citizenship or Place of Organization

         United States of America
...............................................................................

Number of               5.      Sole Voting Power                0
Shares                ........................................................
Beneficially
Owned                   6.      Shared Voting Power              5,690,977
by Each             ........................................................
Reporting
Person                  7.      Sole Dispositive Power           0
With                  ........................................................

                        8.      Shared Dispositive Power         5,690,977
...............................................................................

9.      Aggregate Amount Beneficially Owned by Each Reporting Person

        5,690,977
...............................................................................

10.     Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
        Instructions)

        [  ]
...............................................................................

11.     Percent of Class Represented by Amount in Row (9)

        5.0%
...............................................................................

12.     Type of Reporting Person:

        HC







                                                             Page 4 of 9 Pages


Item 1(a).      Name of Issuer:

                Primus Telecommunications Group, Incorporated (the "Issuer").

Item 1(b).      Address of Issuer's Principal Executive Offices:

                7901 Jones Branch Drive, Suite 900, McLean, VA 22102.

Item 2(a).      Name of Person Filing

                This  Statement  is filed  on behalf  of each of the following
persons (collectively, the "Reporting Persons"):

                i)   Kingdon Capital Management, LLC ("Kingdon Capital
                     Management"); and

                ii)  Mark Kingdon ("Mr. Kingdon").

                This Statement  relates to Shares (as defined herein) held for
the  accounts  of  each  of  Kingdon  Associates,  L.P.,  a New  York  limited
partnership ("Kingdon Associates"), M. Kingdon Offshore Ltd., a Cayman Islands
exempted company ("Kingdon Offshore"), and Kingdon Family Partnership, L.P., a
New York limited partnership ("Kingdon Family  Partnership").  Kingdon Capital
Management serves as investment manager to each of Kingdon Associates, Kingdon
Offshore and Kingdon Family  Partnership.  In such capacity,  Kingdon  Capital
Management may be deemed to have voting and dispositive  power over the Shares
held for the  accounts of each of Kingdon  Associates,  Kingdon  Offshore  and
Kingdon Family  Partnership.  Mr. Kingdon is the managing member and president
of Kingdon Capital Management.

Item 2(b).      Address of Principal Business Office or, if None, Residence

                The  address  of the  principal  business  office  of  each of
Kingdon  Capital  Management  and Mr.  Kingdon is 152 West 57th  Street,  50th
Floor, New York, New York 10019.

Item 2(c).      Citizenship

                i)   Kingdon Capital Management is a Delaware limited liability
                     company; and

                ii)  Mr. Kingdon is a citizen of the United States of America.

Item 2(d).      Title of Class of Securities:

                Common Stock, par value $0.01 per share (the "Shares").

Item 2(e).      CUSIP Number:

                741929103





                                                             Page 5 of 9 Pages


Item 3.         If This Statement is Filed Pursuant to ss.ss.240.13d-1(b) or
                240.13d-2(b) or (c), Check Whether the Person Filing is a:

                This Item 3 is not applicable.

Item 4.         Ownership:

Item 4(a)       Amount Beneficially Owned:

                As of August 17, 2006, each of Kingdon Capital  Management and
Mr. Kingdon may be deemed to beneficially  own 5,690,977  Shares.  This amount
consists of: (A) 1,616,000 Shares held for the account of Kingdon  Associates;
(B) 3,841,877 Shares held for the account of Kingdon Offshore; and (C) 233,100
Shares held for the account of Kingdon Family Partnership.

Item 4(b)       Percent of Class:

                The  number  of  Shares  of  which  each  of  Kingdon  Capital
Management  and  Mr.  Kingdon  may  be  deemed  to  be  the  beneficial  owner
constitutes  approximately  5.0% of the total  number  of  Shares  outstanding
(based upon  information  provided by the Issuer in its most recent  quarterly
report on Form 10-Q filed with the Securities and Exchange  Commission,  there
were 113,833,827 Shares outstanding as of July 31, 2006).

Item 4(c)       Number of Shares of which such person has:

Kingdon Capital Management:
- ---------------------------

(i) Sole power to vote or direct the vote:                          5,690,977

(ii) Shared power to vote or direct the vote:                               0

(iii) Sole power to dispose or direct the disposition of:           5,690,977

(iv) Shared power to dispose or direct the disposition of:                  0



Mr. Kingdon:
- ------------

(i) Sole power to vote or direct the vote:                                  0

(ii) Shared power to vote or direct the vote:                       5,690,977

(iii) Sole power to dispose or direct the disposition of:                   0

(iv) Shared power to dispose or direct the disposition of:          5,690,977


Item 5.         Ownership of Five Percent or Less of a Class:

                This Item 5 is not applicable.

Item 6.         Ownership of More than Five Percent on Behalf of
                Another Person:

                This Item 6 is not applicable.






                                                             Page 6 of 9 Pages



Item 7.         Identification  and  Classification  of the  Subsidiary  Which
                Acquired the Security  Being Reported on By the Parent Holding
                Company:

                See disclosure in Item 2 hereof.

Item 8.         Identification and Classification of Members of the Group:

                This Item 8 is not applicable.

Item 9.         Notice of Dissolution of Group:

                This Item 9 is not applicable.

Item 10.        Certification:

                By signing below each of the Reporting Persons certifies that,
to the best of their  knowledge and belief,  the securities  referred to above
were not  acquired  and are not held for the  purpose of or with the effect of
changing or  influencing  the control of the issuer of the securities and were
not acquired and are not held in connection  with or as a  participant  in any
transaction having that purpose or effect.






                                                             Page 7 of 9 Pages

                                   SIGNATURE

         After reasonable inquiry and to the best of my knowledge and belief,
the undersigned certifies that the information set forth in this statement is
true, complete and correct.

Date: August 17, 2006               KINGDON CAPITAL MANAGEMENT, LLC


                                    By:     /s/ William Walsh
                                          -----------------------------------
                                    Name:   William Walsh
                                    Title:  Chief Financial Officer


Date: August 17, 2006               MARK KINGDON


                                    /s/ Mark Kingdon
                                    -----------------------------------------







                                                             Page 8 of 9 Pages



                                 EXHIBIT INDEX


Ex.                                                                   Page No.
- ---                                                                   --------

A.      Joint Filing Agreement, dated August 17, 2006 by and
        among Kingdon Capital Management, LLC and Mark Kingdon....         9






                                                             Page 9 of 9 Pages


                                   EXHIBIT A

                            JOINT FILING AGREEMENT

                The  undersigned  hereby agree that the  statement on Schedule
13G with respect  to  the  Common  Stock  of  Primus Telecommunications Group,
Incorporated  dated  as  of August 17, 2006  is, and  any  amendments  thereto
(including amendments on Schedule 13D) signed by each of the undersigned shall
be, filed on behalf  of  each  of  us  pursuant to and in  accordance with the
provisions  of  Rule 13d-1(k)  under  the  Securities Exchange Act of 1934, as
amended.

Date: August 17, 2006               KINGDON CAPITAL MANAGEMENT, LLC


                                    By:     /s/ William Walsh
                                          -----------------------------------
                                    Name:   William Walsh
                                    Title:  Chief Financial Officer


Date: August 17, 2006               MARK KINGDON


                                    /s/ Mark Kingdon
                                    -----------------------------------------