EXHIBIT 3.6

                         FIRST AMENDMENT TO THE BY-LAWS
                                       OF
                            ILLUMINET HOLDINGS, INC.



         Pursuant to the Annual Meeting of Stockholders of Illuminet Holdings,
Inc., (f/k/a U.S. Telnet Holdings, Inc. and USTN Holdings, Inc.) a Delaware
corporation (the "Corporation"), dated June 13, 1996, the By-Laws of the
Corporation are hereby amended as follows:

     1. Article III,  Section 2 of the By-Laws is hereby amended and restated in
its entirety so as to read as follows:

                  SECTION 2. NUMBER OF DIRECTORS. The number of directors of the
                  Corporation  which  shall  constitute  the entire  Board shall
                  initially  be sixteen (16) but such number may be changed from
                  time to time to a number  not less than five (5) nor more than
                  sixteen (16) by resolution adopted by a majority of the entire
                  Board;  provided,   however,  that  the  number  of  directors
                  constituting  the entire  Board shall not be  decreased by the
                  Board of Directors below the number then in office unless such
                  decrease  shall  become  effective  at any  annual  meeting of
                  stockholders,  The Board shall be divided into three  classes,
                  which are hereby  designated  Class I, Class II and Class III.
                  The term of  office of the  initial  Class I  directors  shall
                  expire at the 1997 Annual Meeting of Stockholders; that of the
                  initial  Class II  directors  at the 1998  Annual  Meeting  of
                  Stockholders;  and that of the initial  Class III directors at
                  the  1999  Annual  Meeting  of  Stockholders.  At each  annual
                  meeting  after  the  initial   classification   of  directors,
                  directors  to replace  those whose terms expire at such annual
                  meeting  shall be  elected  to hold  office  until  the  third
                  succeeding  annual meeting.  The directors shall be elected at
                  the annual meeting of the stockholders and each director shall
                  be elected to serve until his  successor  shall be elected and
                  shall qualify. As used in these By-Laws,  "entire Board" means
                  the total number of directors  the  Corporation  would have if
                  there were no vacancies.

          2. The following  shall be added to the end of Article III,  Section 5
of the By-Laws.

                  After  January  1,  1997,  directors  may  not be  elected  or
                  re-elected to the Board after  attaining the age of sixty-five
                  years old.  Directors who attain the age of  sixty-five  years
                  old during  their term will be allowed to complete  their full
                  term.





<PAGE>







         3.  Article VI of the  By-Laws is hereby  amended  and  restated in its
entirety so as to read as follows:


                                   ARTICLE VI

                                   AMENDMENTS

     These  By-Laws  may be altered or  repealed  and By-Laws may be made at any
annual meeting of the  stockholders  or at any special meeting thereof if notice
of the  proposed  alteration  or  repeal  or  By-Law  or  By-Laws  to be made be
contained in the notice of such special  meeting,  by the affirmative  vote of a
majority of the stock issued and outstanding and entitled to vote thereat, or by
the  affirmative  vote of a majority of the Board of  Directors,  at any regular
meeting of the Board of  Directors,  or at any  special  meeting of the Board of
Directors if notice of the proposed  alteration or repeal,  or By-Law or By-Laws
to be made,  be  contained  in the  notice of such  special  meeting;  provided,
however,  that the  affirmative  vote of  two-thirds  (2/3) of a majority of the
stock issued and  outstanding  and entitled to vote thereat shall be required to
amend Article III, Section 2 of these By-Laws.

IN WITNESS WHEREOF, the By-Laws are so amended as of this 13th day of June 1996.




                                                   /s/Daniel E. Weiss
                                                      Secretary