AMENDMENT NO. 1 TO
                    THE WARRANT REGISTRATION RIGHTS AGREEMENT

          AMENDMENT NO. 1 dated as of April 30, 1999 to the Warrant Registration
Rights  Agreement,  dated as of  February  4,  1999  (the  "Registration  Rights
Agreement")  among  KMC  Telecom  Holdings,   Inc.  (the  "Company"),   Newcourt
Commercial  Finance  Corporation  ("Newcourt"),  and Lucent  Technologies,  Inc.
("Lucent").
                               W I T N E S S E T H

          WHEREAS,   Newcourt   and  Lucent  have   certain   rights  under  the
Registration  Rights Agreement to have the Company register  securities owned by
them;

          WHEREAS, the Company has issued to First Union Investors, Inc. ("First
Union")  Preferred  Stock  Warrants 2 (as defined  below) and has entered into a
warrant  registration  rights  agreement with First Union,  dated as of the date
hereof (the "Registration Rights Agreement 2") giving First Union certain rights
to have the Company register securities owned by First Union;

          WHEREAS,  the parties hereto desire to make certain  amendments to the
Registration  Rights  Agreement to reconcile the rights  granted to Newcourt and
Lucent under the  Registration  Rights Agreement and the rights granted to First
Union under the Registration Rights Agreement 2;

          NOW,  THEREFORE,  in  consideration of the premises and for other good
and  valuable  consideration,  the receipt and  sufficiency  of which are hereby
acknowledged, the parties hereto hereby agree as follows:

          1. DEFINED TERMS.  Unless  otherwise  defined herein,  all capitalized
terms defined in the  Registration  Rights Agreement and used herein are so used
as so defined.  In  addition,  the  following  terms shall have the meanings set
forth below:

          "PREFERRED  STOCK  WARRANTS  2" means  Warrants  issued to  holders of
Series E Preferred Stock pursuant to the Warrant  Agreement 2, each such Warrant
initially  entitling the holder  thereof to purchase  0.471756  shares of Common
Stock at an exercise price of $.01 per share, and any Springing  Warrants issued
to First Union  under the Warrant  Agreement  as amended by  Amendment  No. 1 to
Warrant Agreement dated as of April 30, 1999.

          "PURCHASE  AGREEMENT 2" means the Securities  Purchase Agreement dated
as of April 30, 1999 between the Company and First Union Investors, Inc.

          "REGISTRATION  RIGHTS  AGREEMENT"  has the  meaning  specified  in the
introductory paragraph of this Amendment;  "REGISTRATION RIGHTS AGREEMENT 2" has
the meaning specified in the recitals to this Amendment.


<PAGE>

          "WARRANT  AGREEMENT 2" means the Warrant  Agreement  dated as of April
30, 1999 among the Company, First Union Investors,  Inc. and The Chase Manhattan
Bank as Warrant Agent.

          2.  AMENDMENT  TO  SECTIONS  2(B) AND (C) OF THE  REGISTRATION  RIGHTS
AGREEMENT.

          (a) For purposes of the second paragraph of Paragraph (b) of Section 2
of the Registration  Rights Agreement,  "Holders" shall be deemed to include, in
addition to the record  holders of the warrants and  Springing  Warrants  issued
pursuant  to the  Warrant  Agreement  and  holders  of Common  Shares  (or other
securities)  received upon exercise thereof,  the record holders of the warrants
issued under the Warrant  Agreement 2 and the holders of Common Shares (or other
securities) received upon exercise thereof;

          (b) For  purposes of  Paragraph  (c) of Section 2 of the  Registration
Rights  Agreement,  "Holders"  shall be deemed to  include,  in  addition to the
record  holders of the warrants and Springing  Warrants  issued  pursuant to the
Warrant  Agreement and holders of Common Shares (or other  securities)  received
upon  exercise  thereof,  the record  holders of the  warrants  issued under the
Warrant  Agreement  2 and the  holders of Common  Shares  (or other  securities)
received upon exercise thereof.

          3. Except as expressly  amended  hereby,  all of the provisions of the
Registration  Rights  Agreement are hereby  affirmed and shall  continue in full
force and effect in accordance with their terms.

          4. This Amendment  shall be governed and construed in accordance  with
the laws of the  state  of  Delaware  applicable  to  agreements  made and to be
performed  entirely  within  such state,  without  regard to the  principles  of
conflicts of laws thereof.

          5. This Amendment may be executed in one or more counterparts, each of
which  shall be  deemed an  original  and all of which,  taken  together,  shall
constitute one and the same instrument.

                                       C-2
<PAGE>

          IN WITNESS  WHEREOF,  the undersigned  have executed,  or caused to be
executed, this Amendment as of the date first above written.

                                              KMC TELECOM HOLDINGS, INC.


                                              By: /s/ James D. Greenfell
                                                  ______________________________
                                                  Name:  James D. Greenfell
                                                  Title: Chief Financial Officer


                                              NEWCOURT COMMERCIAL FINANCE
                                                       CORPORATION


                                              By:  /s/ John P. Sirico
                                                  ______________________________
                                                  Name:  John P. Sirico, II
                                                  Title: Vice President

                                              LUCENT TECHNOLOGIES INC.


                                              By:  /s/ Leslie L. Rogers
                                                  ______________________________
                                                  Name:  Leslie L. Rogers
                                                  Title: Managing Director




Signature Page to
Amendment No. 1 to
Warrant Registration
Rights Agreement