EXHIBIT 10.5(b)

                                                 [EXECUTION COUNTERPART]



                                AMENDMENT NO. 1

  AMENDMENT NO. 1 dated as of January 13, 1998, between MEDIACOM CALIFORNIA LLC,
a limited liability company duly organized and validly existing under the laws
of the State of Delaware ("Mediacom California"), MEDIACOM DELAWARE LLC, a
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limited 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 California and
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Mediacom Delaware, the "Borrowers"); each of the banks that is a signatory
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hereto (individually, a "Lender" and, collectively, the "Lenders"); THE CHASE
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MANHATTAN BANK, as administrative agent for the Lenders (in such capacity,
together with its successors in such capacity, the "Administrative Agent"); and
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FIRST UNION NATIONAL BANK, as documentation agent (in such capacity, the
                                                                        
"Documentation Agent").
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  The Borrowers, the Lenders, the Administrative Agent and the Documentation
Agent are parties to a Second Amended and Restated Credit Agreement dated as of
June 24, 1997 (as heretofore modified and supplemented and in effect on the date
hereof, the "Credit Agreement"), providing, subject to the terms and conditions
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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. 1,
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terms defined in the Credit Agreement are used herein as defined therein.

  Section 2.  Amendments.  Upon the execution and delivery of this Amendment No.
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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 9.01(b) of the Credit Agreement is hereby amended to read in 
its entirety as follows:

                                Amendment No. 1
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                                      -2-


       "(b)  Any Borrower or any Subsidiary of a Borrower shall default in the
     payment when due of any principal of or interest on any of its other
     Indebtedness aggregating $500,000 or more; or any event specified in any
     note, agreement, indenture or other document evidencing or relating to any
     such Indebtedness shall occur if the effect of such event is to cause, or
     (without the lapse of time or the taking of any action, other than the
     giving of notice) to permit the holder or holders of such Indebtedness (or
     a trustee or agent on behalf of such holder or holders) to cause, such
     Indebtedness to become due, or to be prepaid in full (whether by
     redemption, purchase, offer to purchase or otherwise), prior to its stated
     maturity; or the Borrowers shall default in the payment when due of any
     amount aggregating $500,000 or more under any Interest Rate Protection
     Agreement; or any event specified in any Interest Rate Protection Agreement
     shall occur if the effect of such event is to cause, or (with the giving of
     any notice or the lapse of time or both) to permit, termination or
     liquidation payment or payments aggregating $500,000 or more to become due;
     or"

     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.

                                Amendment No. 1
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                                      -3-


  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 CALIFORNIA LLC
               
                              By  MEDIACOM LLC, a Member
               
               
                              By_______________________________ 
                               Title: Manager
               
               
                              MEDIACOM DELAWARE LLC
               
                              By  MEDIACOM LLC, a Member
               
               
                              By_______________________________ 
                               Title: Manager
               
               
                              MEDIACOM ARIZONA LLC
               
                              By  MEDIACOM LLC, a Member
               
               
                              By_______________________________ 
                               Title: Manager
               
               
                              THE CHASE MANHATTAN BANK,
                              individually and as                       
                              Administrative Agent
               
               
                              By______________________________                 
                               Title:
                              
                                Amendment No. 1
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                                      -4-


                              FIRST UNION NATIONAL BANK,
                              individually and as
                              Documentation Agent
 
 
                              By________________________________                
                               Title:
 
                              FIRST NATIONAL BANK OF CHICAGO
 
                              By________________________________
                              Title:
 
 
                              MELLON BANK, N.A.
 
 
                              By________________________________
                               Title:
 
 
                              CIBC INC.
 
 
                              By________________________________
                               Title:
 
 
                              BANK OF MONTREAL
 
                              By________________________________
                              Title:

                                Amendment No. 1
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