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                                                                 EXHIBIT 10.1(b)
                                AMENDMENT NO. 1

     AMENDMENT NO. 1 dated as of December 17, 1999, between MEDIACOM SOUTHEAST
LLC, a limited liability company duly organized and validly existing under the
laws of the State of Delaware ("Mediacom Southeast"); MEDIACOM CALIFORNIA LLC, a
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limited liability company duly organized and validly existing under the laws of
the State of Delaware ("Mediacom California"); MEDIACOM DELAWARE LLC, a limited
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liability company duly organized and validly existing under the laws of the
State of Delaware ("Mediacom Delaware"); MEDIACOM ARIZONA LLC, a limited
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liability company duly organized and validly existing under the laws of the
State of Delaware ("Mediacom Arizona" and, together with Mediacom Southeast,
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Mediacom California, Mediacom Delaware, the "Borrowers"), the lenders party
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thereto (the "Lenders") and The Chase Manhattan Bank, as Administrative Agent
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for the Lenders.

     The Borrowers, the Lenders and the Administrative Agent are parties to a
Credit Agreement dated as of September 30, 1999 ( the "Credit Agreement"),
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providing, subject to the terms and conditions thereof, for extensions of credit
to be made by said Lenders to the Borrowers. The parties wish to amend the
Credit Agreement in certain respects, and accordingly, the parties hereto hereby
agree as follows:

     Section 1. Definitions. Except as otherwise defined in this Amendment No.
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1, terms defined in the Credit Agreement are used herein as defined therein.

     Section 2. Amendments. Upon the execution and delivery of this Amendment
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No. 1 by the Borrowers and Majority Lenders, but effective as of the date
hereof, the Credit Agreement shall be amended as follows:

     2.01. References in the Credit Agreement (including references to the
Credit Agreement as amended hereby) to "this Agreement" (and indirect references
such as "hereunder", "hereby", "herein" and "hereof") shall be deemed to be
references to the Credit Agreement as amended hereby.

     2.02. Section 8.13 of the Credit Agreement is hereby amended to read in its
entirety as follows:

     "8.13 Interest Rate Protection Agreements. The Borrowers will, on or prior
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   to April 30, 2000, enter into, and thereafter maintain in full force and
   effect, one or more Interest Rate Protection Agreements with one or more of
   the Lenders or their affiliates (and/or with a bank or other financial
   institution having capital, surplus and undivided profits of at least
   $500,000,000), that effectively enables the Borrowers (in a manner
   satisfactory to the Majority Lenders) to protect themselves, in a manner and
   on terms reasonably satisfactory to the Majority Lenders, against adverse
   fluctuations in the three-month London interbank offered rates as to a
   notional principal amount which, together with that portion of the aggregate
   outstanding principal amount of Indebtedness of the Borrowers bearing a fixed
   rate of interest, shall in the aggregate be at least equal to 50%


                                 Amendment No. 1
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     of the aggregate outstanding principal amount of the Indebtedness
     (including Affiliate Subordinated Indebtedness) of the Borrowers."

  Section 3.  Miscellaneous.  Except as herein provided, the Credit Agreement
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shall remain unchanged and in full force and effect.  This Amendment No. 1 may
be executed in any number of counterparts, all of which taken together shall
constitute one and the same amendatory instrument and any of the parties hereto
may execute this Amendment No. 1 by signing any such counterpart.  This
Amendment No. 1 shall be governed by, and construed in accordance with, the law
of the State of New York.
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  IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 1 to be
duly executed and delivered as of the day and year first above written.

                                        MEDIACOM SOUTHEAST LLC
                                        MEDIACOM CALIFORNIA LLC
                                        MEDIACOM DELAWARE LLC
                                        MEDIACOM ARIZONA LLC

                                        By  MEDIACOM LLC, a Member

                                        By:_________________________
                                           Name:
                                           Title:


                                        THE CHASE MANHATTAN BANK,
                                        as Administrative Agent

                                        By:_________________________
                                           Name:
                                           Title:


                                 Amendment No. 1
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