Exhibit 99.1

                            AMENDMENT TO REGISTRATION AGREEMENT
 
                 THIS AMENDMENT AGREEMENT (this "Amendment") is entered into as
of November 22, 1996 to the Registration Agreement, dated as of August 23, 1996
(the  "Registration  Agreement") by and among  Nextel  Communications,  Inc., a
Delaware corporation ("Nextel"), Grupo Comunicaciones San Luis. S.A. de C.V., a
Mexican corporation ("Grupo") and each of the persons listed in Schedule 1 (the
"Sellers").

                  For good and valuable  consideration,  the receipt of which is
hereby acknowledged by the parties, the parties agree as follows:

                  1.       Definitions.  Capitalized  terms  that  are  used
but not  otherwise  defined  have the meanings given to such terms in the
Registration Agreement.

                  2.       Amendment  to definition of "Registration  Period".
Section 2.3(a)(i) of the Registration Agreement is hereby amended and restated
in its entirety to read as follows:

              "(i) subject to Section  2.3(b) below, keep the Registration
                   Statement,  effective for the lesser of (A)(1) in respect
                   of the First  Tranche of  Registrable  Securities, a period
                   of 60 days  after the First  Seller Share Exchange or (2) in
                   respect of the Second Tranche of  Registrable Securities, a
                   period of 30 days after the Second  Seller Share Exchange
                   (plus in the case of each of (1) and (2) any  number of days
                   that the  holders of  Registrable  Securities  are unable to
                   use a prospectus  pursuant to Section 2.3(b) below except if
                   such inability arises from a change in the proposed plan of
                   distribution  by holders of Registrable  Securities as
                   contemplated  by Section 2.5, it being  understood that this
                   Amendment does not constitute such a change in the proposed
                   plan of  distribution)  or (B) a period until each such
                   holder shall have  completed the distributin  described in
                   the Registration Statement (the lesser of (A) and (B) being
                   herein  referred to as the "Registration Period") (it being
                   understood that if Nextel uses the same Registration
                   Statement for purposes of Section 2.1(b) as used in Section
                   2.1(a),  the  periods  referred  to above shall with respect
                   to the Second  Tranche of Registrable Securities refer to
                   periods after the Second Seller Share Exchange);".

                   3.   Miscellaneous.

                   (a) Law  Governing.  This  Amendment  shall be construed and
enforced in accordance with and  shall be governed by the laws of the State of
New York applicable to contracts executed in and to be fully performed in that
state.

                   (b)  Counterparts. This Amendment may be executed in any
number of counterparts, each of which when so executed and delivered shall
constitute an original and all together shall constitute one Agreement.






                  (c) Headings. The headings in this Amendment are for purposes
of  reference only and shall not be considered in construing this Amendment.





































                                        2




         IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date and year first above written.

                           NEXTEL COMMUNICATIONS, INC.


                           By:/s/Thomas J. Sidman
                              Name: Thomas J. Sidman
                              Title: Vice President

                           GRUPO COMUNICACIONES SAN LUIS, S.A. de C.V.


                           By:/s/Miguel Fernando Valladares Garcia
                              Name: Miguel Fernando Valladares Garcia
                              Title: 


                            /s/Miguel Fernando Valladares Garcia
                            Miguel Fernando Valladares Garcia


                            /s/Carlos Guerrero Gonzales
                            Carlos Guerrero Gonzalez

                            /s/Rosa Maria Garcia de Valladares
                            Rosa Maria Garcia de Valladares

                            /s/Rosa Maria Valladares Garcia
                            Rosa Maria Valladares Garcia
  
                            /s/Juan Carlos Valladares Garcia
                            Juan Carlos Valladares Garcia

                            /s/Josefina Valladares de Muriel
                            Josefina Valladares de Muriel

                            /s/Rosario Valladares de Gavino
                            Rosario Valladares de Gavino

                            /s/Pablo Valladares Garcia
                            Pablo Valladares Garcia

                            /s/Benigno Perez Lizaur
                            Benigno Perez Lizaur

                            /s/Mauricio Meade Laing
                            Mauricio Meade Laing




                                    3




                                    SCHEDULE 1
                                   (the Sellers)



                          Miguel Fernando Valladares Garcia
                              Carlos Guerrero Gonzalez
                           Rosa Maria Garcia de Valladares
                            Rosa Maria Valladares Garcia
                            Juan Carlos Valladares Garcia
                            Josefina Valladares de Muriel
                            Rosario Valladares de Gavino
                               Pablo Valladares Garcia
                                Benigno Perez Lizaur
                                Mauricio Meade Laing















                                     4