<PAGE>
 
                                                                 Exhibit 10.5(e)

                                                                [Execution Copy]


                                 AMENDMENT NO. 4 TO
                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

        AMENDMENT NO. 4 TO SECOND AMENDED AND RESTATED CREDIT AGREEMENT dated as
of January 26, 1999, between MEDIACOM CALIFORNIA LLC, a Delaware limited
liability company ("Mediacom California"); MEDIACOM DELAWARE LLC, a Delaware
                    -------------------
limited liability company ("Mediacom Delaware"); MEDIACOM ARIZONA LLC, a
                            -----------------
Delaware limited liability company ("Mediacom Arizona" and, together with
                                     ----------------
Mediacom California and Mediacom Delaware, the "Borrowers"); each of the lenders
                                                ---------
that is a signatory hereto identified under the caption "LENDERS" on the
signature pages hereto (each, individually, a "Lender" and, collectively, the
"Lenders") and The Chase Manhattan Bank, as Administrative Agent (the
 -------
"Administrative Agent").
 --------------------

        The Borrowers, the Lenders, the Administrative Agent and First Union
National Bank, as Documentation Agent, are party 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 thereof, for loans in an
aggregate principal amount up to but not exceeding $100,000,000. The Borrowers
wish to increase the Revolving Credit Commitments under the Credit Agreement
from $69,700,000 to $99,400,000 concurrently with a prepayment of the Term A
Loans in an amount equal to such increase and to amend the Credit Agreement in
certain other respects. The Lenders and the Administrative Agent are willing to
so agree and, accordingly, the parties hereto hereby agree as follows:

        Section 1.  Definitions.  Except as otherwise defined in this Amendment
                    -----------
No. 4, terms defined in the Credit Agreement are used herein as defined therein.

        Section 2.  Amendments.  Subject to the satisfaction of the conditions
                    ----------
precedent specified in Section 5 below, 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 1.01 of the Credit Agreement shall be amended by adding
the following new definitions (to the extent not already included in said
Section 1.01) and inserting

                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -2-



the same in the appropriate alphabetical locations and amending in their
entirety the following definitions (to the extent already included in said
Section 1.01), as follows:

        "Amendment No. 4" shall mean Amendment No. 4 hereto dated as of January
         ---------------
     26, 1999 between the Borrowers, the Lenders, the Administrative Agent and
     the Documentation Agent.

        "Amendment No. 4 Effective Date" shall mean the date upon which the
         ------------------------------
     amendments provided for in Section 2 of Amendment No. 4 hereto shall become
     effective.
 
        "Revolving Credit Commitment" shall mean, as to each Revolving Credit
         ---------------------------
     Lender, the obligation of such Lender to make Revolving Credit Loans in an
     aggregate principal amount at any one time outstanding up to but not
     exceeding the amount set forth opposite the name of such Lender on Schedule
     1 to Amendment No. 4 or, in the case of a Person that becomes a Revolving
     Credit Lender pursuant to an assignment permitted under Section 11.06(b)
     hereof, as specified in the respective instrument of assignment pursuant to
     which such assignment is effected (as the same may be reduced from time to
     time pursuant to Section 2.03 or 2.09 hereof, or increased or reduced in
     connection with any assignment pursuant to Section 11.06(b) hereof). The
     original aggregate principal amount of the Revolving Credit Commitments
     (after giving effect to Amendment No. 4) is $99,400,000.

        2.03. Section 2.01 of the Credit Agreement is hereby amended by
inserting a new paragraph (f) at the end thereof to read as follows:

        "(f)  Amendment No. 4 Effective Date.  On the Amendment No. 4 Effective
              ------------------------------
     Date, all of the outstanding Term A Loans shall be prepaid be in full by
     the Borrowers as provided in Section 5(ii) of Amendment No. 4 hereto.
     Following such prepayment, all references in this Agreement to "Term A
     Loans", "Term A Lenders" and the like shall be deemed to be inoperative."

        2.04. The schedule set forth in Section 2.03(a) of the Credit Agreement
is hereby amended in its entirety to read as follows:

<TABLE>
<CAPTION>
              (A)                              (B)                             (C)
        Revolving Credit                 Revolving Credit               Revolving Credit
      Commitment Reduction             Commitments Reduced             Commitment Reduced
       Date Falling on or                by the Following               to the Following
          Nearest to:                        Amounts:                        Amounts:
          -----------                        --------                        --------
<S>                                         <C>                             <C>
         March 31, 1999                     $1,600,000                      $97,800,000
</TABLE>

                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -3-

<TABLE>
<CAPTION>

<S>                                         <C>                             <C>
         June 30, 1999                      $1,600,000                      $96,000,000
         September 30, 1999                 $1,600,000                      $94,600,000
         December 31, 1999                  $1,600,000                      $93,000,000
                                                               
         March 31, 2000                     $2,275,000                      $90,725,000
         June 30, 2000                      $2,275,000                      $88,450,000
         September 30, 2000                 $2,275,000                      $86,175,000
         December 31, 2000                  $2,275,000                      $83,900,000
                                                               
         March 31, 2001                     $2,950,000                      $80,950,000
         June 30, 2001                      $2,950,000                      $78,000,000
         September 30, 2001                 $2,950,000                      $75,050,000
         December 31, 2001                  $2,950,000                      $72,100,000
                                                               
         March 31, 2002                     $3,400,000                      $68,700,000
         June 30, 2002                      $3,400,000                      $65,300,000
         September 30, 2002                 $3,400,000                      $61,900,000
         December 31, 2002                  $3,400,000                      $58,500,000
                                                               
         March 31, 2003                     $3,850,000                      $54,650,000
         June 30, 2003                      $3,850,000                      $50,800,000
         September 30, 2003                 $3,850,000                      $46,950,000
         December 31, 2003                  $3,850,000                      $43,100,000
                                                               
         March 31, 2004                     $4,525,000                      $38,575,000
         June 30, 2004                      $4,525,000                      $34,050,000
         September 30, 2004                 $4,525,000                      $29,525,000
         December 31, 2004                  $4,525,000                      $25,000,000
                                                               
         March 31, 2005                     $7,850,000                      $17,150,000
         June 30, 2005                      $7,850,000                      $ 9,300,000
         September 30, 2005                 $9,300,000                      $         0
</TABLE>

        2.05. Section 8.09(d)(ii) of the Credit Agreement shall be amended in
its entirety to read as follows:

        "(ii) after giving effect to such payment during any fiscal quarter (the
     "current fiscal quarter"), and to the making of any Capital Expenditures
      ----------------------
     pursuant to the last paragraph of Section 8.12 hereof during the current
     fiscal quarter, the Borrowers would (as at the last day of the most recent
     fiscal quarter immediately prior to the current fiscal quarter) have been
     in compliance on a pro forma basis with Section 8.10 hereof and the Senior
     Leverage Ratio calculated on a pro forma basis is at the time less than
     5.50 to 1 

                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -4-


     (or, if lower, the applicable requirement at the time under Section 8.10(a)
     hereof), the determination of such compliance and such Senior Leverage
     Ratio to be determined as if (x) for purposes of calculating the Senior
     Leverage Ratio and the Total Leverage Ratio, the amount of such payment,
     together with the amount of any such Capital Expenditures, were added to
     Indebtedness, and (y) for purposes of calculating the Interest Coverage
     Ratio and Fixed Charge Coverage Ratio, the amount of such payment (and any
     Cure Monies received during the period for which the Interest Coverage
     Ratio or Fixed Charge Coverage Ratio is calculated), together with the
     amount of any such Capital Expenditures, represented additional principal
     of the Loans outstanding hereunder at all times during the respective
     fiscal quarter for which such Ratios are calculated and the amount of
     interest that would have been payable hereunder during such fiscal quarter
     were recalculated to take into account such additional principal; and"

        2.06. Section 8.12 of the Credit Agreement shall be amended by adding a
new paragraph at the end thereof to read as follows:

        "In addition to the Capital Expenditures permitted under the preceding
     paragraph, the Borrowers and their Subsidiaries may make additional Capital
     Expenditures during any fiscal quarter in such amounts as would be
     permitted under Section 8.09(d)(ii) (in the case of a payment of principal
     of Affiliate Subordinated Indebtedness, as if such Capital Expenditure
     constituted a payment in respect of Supplemental Capital thereunder)."

        2.07. Section 8.13 of the Credit Agreement shall be amended in its
entirety to read as follows:

        "8.13 Interest Rate Protection Agreements. The Borrowers will within 90
              -----------------------------------
     days of the Effective Date, 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% of the aggregate outstanding principal amount of the Indebtedness
     (including Affiliate Subordinated Indebtedness) of the Borrowers."

        Section 3.  Consent.  Subject to the satisfaction of the conditions
                    -------
precedent specified in Section 5 below, but effective as of the date hereof, the
Lenders hereby consent to the amendment of the instruments and other documents
evidencing or relating to Affiliate

                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -5-

Subordinated Indebtedness to permit the rate of interest payable in respect
thereof to be equal to a rate of interest payable by Mediacom on its 8-1/2%
Senior Notes due 2008.

        Section 4.  Representations and Warranties.  Each Borrower represents
                    ------------------------------
and warrants to the Lenders that the representations and warranties set forth in
Section 7 of the Credit Agreement are true and complete on the date hereof as if
made on and as of the date hereof and as if each reference in said Section 7 to
"this Agreement" and "the Notes" included reference to this Amendment No. 4 and
to the New Notes (as defined herein below).

        Section 5.  Conditions Precedent.  The effectiveness of the amendments
                    --------------------
set forth in Section 2 above, and the consent set forth in Section 3 above, is
subject to: (i) the condition that this Amendment No. 4 shall have been executed
and delivered by each Borrower, each Lender and the Administrative Agent (and
that the Parent Guarantors shall have executed and delivered their confirmation
and consent provided for on the signature pages hereto), in each case on or
before February 15, 1999, (ii) the prepayment, in accordance with the provisions
of Section 2.08 of the Credit Agreement, of Term A Loans in an aggregate amount
of $29,700,000 (which amount is the aggregate principal amount of Term A Loans
outstanding on the date hereof) together with the payment of all interest
accrued thereon in accordance with the provisions of Section 3.02 of the Credit
Agreement (and any amounts that may be payable under Section 5.05 of the Credit
Agreement in connection therewith), which prepayment may be made from any
source, including from the increase in Revolving Credit Commitments contemplated
hereby, and (iii) the receipt by the Administrative Agent of the following
documents, each of which shall be satisfactory to the Administrative Agent (and
to the extent specified below, to each Lender) in form and substance:

        (a)  New Notes.  A new promissory note for each Revolving Credit Lender,
             ---------                                                          
     delivered by the Borrowers in exchange for the Revolving Credit Note
     heretofore delivered to such Revolving Credit Lender, in substantially the
     form of Exhibit A-1 to the Credit Agreement, dated the date of the
     Revolving Credit Note being exchanged, payable to such Revolving Credit
     Lender in a principal amount equal to its Revolving Credit Commitment (as
     increased hereby) and otherwise duly completed.  Each such promissory note
     (a "New Note") shall constitute a "Revolving Credit Note" under the Credit
         --------                                                              
     Agreement as amended hereby.

        (b)  Organizational Matters.  The Administrative Agent shall have
             ----------------------
     received such documents and certificates as the Administrative Agent or as
     Milbank, Tweed, Hadley & McCloy, special New York counsel to Chase, may
     reasonably request relating to the organization, existence and good
     standing of each Credit Party and the authorization of this Amendment No.
     4, all in form and substance reasonably satisfactory to the Administrative
     Agent and its counsel.

                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -6-

        (c)  Opinion of Counsel to the Obligors.  The Administrative Agent
             ----------------------------------                           
     shall have received a favorable written opinion (addressed to the
     Administrative Agent and the Lenders and dated the Amendment No. 4
     Effective Date) of Cooperman, Levitt, Winnikoff, Lester & Newman, P.C.,
     counsel to the Obligors, substantially in the form of Exhibit A, and
     covering such other matters relating to the Obligors, this Agreement or the
     other Loan Documents as the Administrative Agent or any Lender shall
     reasonably request (and each Obligor hereby requests such counsel to
     deliver such opinion).


        (d)  Opinion of Special Counsel.  The Administrative Agent shall have
             --------------------------
     received a favorable written legal opinion (addressed to the Administrative
     Agent and the Lenders and dated the Amendment No. 4 Effective Date) of
     Milbank, Tweed, Hadley & McCloy, special New York counsel to Chase,
     substantially in the form of Exhibit B (and the Administrative Agent hereby
     requests Special Counsel to deliver such opinion).

        (e)  Other Documents. Such other documents as either the Administrative
     Agent or any Lender or Special Counsel may reasonably request.

        Section 6.  Confirmation of Security.  Each Borrower hereby confirms
                    ------------------------
that the obligations of such Borrower under the Credit Agreement as amended by
this Amendment No. 4 shall be entitled to the benefits of the collateral
security provided for pursuant to the Security Agreement.

        Section 7.  Miscellaneous.  Except as herein provided, the Credit
                    -------------
Agreement shall remain unchanged and in full force and effect. This Amendment
No. 4 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. 4 by signing any such counterpart. This
Amendment No. 4 shall be governed by, and construed in accordance with, the law
of the State of New York.

                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -7-

        IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 4
to be duly executed and delivered as of the day and year first above written.


MEDIACOM CALIFORNIA LLC                       MEDIACOM DELAWARE LLC


By                                            By
 Title:                                        Title:


                                              MEDIACOM ARIZONA LLC


                                              By
                                               Title:


                                    LENDERS
                                    -------
                                        

THE CHASE MANHATTAN BANK,                     FIRST UNION NATIONAL BANK
 individually and as Administrative Agent


By                                            By
 Title:                                        Title:


BANK OF MONTREAL                              CIBC INC.


By                                            By
 Title:                                        Title:


THE FIRST NATIONAL BANK                       MELLON BANK, N.A.
 OF CHICAGO


By                                            By
 Title:                                        Title:



                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -8-


        By their signatures below, each of the undersigned Parent Guarantors
under the above-referenced Credit Agreement hereby consents to the foregoing
Amendment No. 4 and confirms that the obligations of the Borrowers under said
Credit Agreement as amended by said Amendment No. 4 shall constitute "Guaranteed
Obligations" under the Guarantee and Pledge Agreement under and as defined in
said Credit Agreement for all purposes of said Guarantee and Pledge Agreement.


MEDIACOM LLC                                     MEDIACOM MANAGEMENT
                                                   CORPORATION



By_____________________                          By_____________________
 Rocco B. Commisso, as                            Title:
  Manager



                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                                                      SCHEDULE 1
                                                              to Amendment No. 4



                          Revolving Credit Commitments
                          ----------------------------
                                        



<TABLE>
<CAPTION>
 
 
Lender                                                  Revolving Credit Commitment
------                                                  ---------------------------
<S>                                                     <C>
The Chase Manhattan Bank                                      $19,880,000.00
First Union National Bank                                     $19,880,000.00
Bank of Montreal                                              $14,910,000.00
CIBC Inc.                                                     $14,910,000.00
The First National Bank of Chicago                            $14,910,000.00
Mellon Bank, N.A.                                             $14,910,000.00
TOTAL                                                         $99,400,000.00
</TABLE>


                      Amendment No. 4 to Credit Agreement
                      -----------------------------------
<PAGE>
 
                                      -1-

                                                                       EXHIBIT A


                  [Form of Opinion of Counsel to the Obligors]

                                                _______, 1999


To the Lenders party to Amendment
No. 4 to the Credit Agreement referred to
below and The Chase Manhattan
Bank, as Administrative Agent


Ladies and Gentlemen:

          We have acted as counsel to Mediacom California LLC ("Mediacom
                                                                --------
California"), Mediacom Delaware LLC ("Mediacom Delaware"), Mediacom Arizona LLC
----------                            -----------------
("Mediacom Arizona" and, together with Mediacom California and Mediacom
  ----------------
Delaware, the "Borrowers") Mediacom LLC ("Mediacom") and Mediacom Management
               ---------                  --------
Corporation (the "Manager", and collectively, together with Mediacom, the
                  -------
"Parent Guarantors") in connection with (i) the Second Amended and Restated
 -----------------
Credit Agreement (the "Credit Agreement") dated as of June 24, 1997, between the
                       ----------------
Borrowers, the lenders party thereto, The Chase Manhattan Bank, as
Administrative Agent, and First Union National Bank, as Documentation Agent,
providing for loans to be made by said lenders to the Borrowers in an aggregate
principal amount not exceeding $100,000,000, (ii) Amendment No. 4 thereto dated
as of January 26, 1999 ("Amendment No. 4") and (iii) the various other
                         ---------------
agreements, instruments and other documents referred to in the next following
paragraph. Terms defined in Amendment No. 4 (including terms incorporated by
reference into Amendment No. 4) are used herein as defined therein; in addition,
the Credit Agreement as amended by Amendment No. 4 is referred to herein as the
"Amended Credit Agreement". This opinion letter is being delivered pursuant to
 ------------------------
Section 5(iii)(c) of Amendment No. 4.

          In rendering the opinions expressed below, we have examined the
following agreements, instruments and other documents:

          (a)  the Credit Agreement;

          (b)  Amendment No. 4;

          (c)  the New Notes being executed and delivered to the Lenders on the
               date hereof (collectively, the "New Notes");
                                               ---------   

                      Opinion of Counsel to the Obligors
                      ----------------------------------
<PAGE>
 
                                      -2-

          (d)  the Confirmation and Consent of the Parent Guarantors appended to
               Amendment No. 4 (the "Confirmation and Consent"); and
                                     ------------------------       

          (e)  such records of the Borrowers and such other documents as we have
               deemed necessary as a basis for the opinions expressed below.

Amendment No. 4, the Amended Credit Agreement, the New Notes and the
Confirmation and Consent are collectively referred to as the "Credit Documents";
                                                              ----------------  
the Borrowers, Mediacom and the Manager are herein collectively referred to as
the "Relevant Parties".
     ----------------  

          We have also examined originals, or copies certified to our
satisfaction, of such corporate records, certificates of public officials of
pertinent states, certificates of corporate officers of the Relevant Parties and
such other instruments or documents as we have deemed necessary as a basis for
the opinions hereinafter set forth. As to questions of fact, we have, to the
extent that such facts were not independently established by us, relied upon
such certificates and we have assumed that any such certificates or other
evidence which was given or dated earlier than the date of this letter has
remained accurate, as far as relevant to the opinions contained herein, from
such earlier date through and including the date of this letter. In rendering
the opinions hereinafter set forth as to factual matters, we have also relied
upon, and assumed the accuracy of, the representations and warranties made in
the Credit Documents by the Relevant Parties. Whenever any statement herein is
qualified by our knowledge, it is intended to indicate that, during the course
of our representation of the Relevant Parties no information that would give us
actual knowledge of the inaccuracy of such statement has come to the attention
of the attorneys presently in this firm and who are actively engaged in the
representation of the Relevant Parties.

          In our examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals and the
conformity with authentic original documents of all documents submitted to us as
copies.

        In rendering the opinions expressed below, we have assumed, with respect
to all of the documents referred to in this opinion letter, that (except, to the
extent set forth in the opinions expressed below, as to the Relevant Parties):

        (i)   such documents have been duly authorized by, have been duly
              executed and delivered by, and constitute legal, valid, binding
              and enforceable obligations of, all of the parties to such
              documents;

        (ii)  all signatories to such documents have been duly authorized; and


                      Opinion of Counsel to the Obligors
                      ----------------------------------
<PAGE>
 
                                      -3-

        (iii) all of the parties to such documents are duly organized and
              validly existing and have the power and authority (corporate,
              limited liability company, partnership or other) to execute,
              deliver and perform such documents.

        Based upon and subject to the foregoing and subject also to the comments
and qualifications set forth below, and having considered such questions of law
as we have deemed necessary as a basis for the opinions expressed below, we are
of the opinion that:

        1.   Each Borrower is a limited liability company duly organized,
     validly existing and in good standing under the laws of the State of
     Delaware. Mediacom is a limited liability company duly organized, validly
     existing and in good standing under the laws of the State of New York. The
     Manager is a corporation, duly organized, validly existing and in good
     standing under the laws of the State of Delaware.

        2.   Each Relevant Party has all requisite power to execute and deliver
     Amendment No. 4 and the New Notes, and to perform its obligations under,
     the Credit Documents to which it is a party. Each Borrower has all
     requisite power to borrow under the Amended Credit Agreement.

        3.   The execution, delivery and performance by each Relevant Party of
     each Credit Document to which it is a party, and the borrowings by each
     Borrower under the Amended Credit Agreement, have been duly authorized by
     all necessary corporate or other action (as the case may be) on the part of
     such Relevant Party.

        4.   Amendment No. 4, the New Notes and the Confirmation and Consent
     have each been duly executed and delivered by each Relevant Party party
     thereto.

        5.   Each of the Credit Documents constitutes the legal, valid and
     binding obligation of each Relevant Party party thereto, enforceable
     against such Relevant Party in accordance with its terms, except as may be
     limited by bankruptcy, insolvency, reorganization, fraudulent conveyance,
     moratorium or other similar laws relating to or affecting the rights of
     creditors generally and except as the enforceability of the Credit
     Documents is subject to the application of general principles of equity
     (regardless of whether considered in a proceeding in equity or at law),
     including, without limitation, (a) the possible unavailability of specific
     performance, injunctive relief or any other equitable remedy and (b)
     concepts of materiality, reasonableness, good faith and fair dealing.

        6.   No authorization, approval or consent of, and no filing or
     registration with, any governmental or regulatory authority or agency of
     the United States of America or the State of New York is required on the
     part of any Relevant Party for the execution and

                      Opinion of Counsel to the Obligors
                      ----------------------------------
<PAGE>
 
                                      -4-

     delivery of Amendment No. 4 or performance by any Relevant Party of the
     Amended Credit Agreement or for the borrowings by each of the Borrowers
     under the Amended Credit Agreement.

        7.   The execution and delivery by each Relevant Party of Amendment No.
     4, and the consummation by each Relevant Party of the transactions
     contemplated by the Amended Credit Agreement do not and will not (a)
     violate any provision of the limited liability company agreement, articles
     of organization, certificate of formation or the charter or by-laws or
     other organizational instrument of any Relevant Party, (b) violate any
     applicable law, rule or regulation, (c) violate any order, writ, injunction
     or decree of any court or governmental authority or agency or any arbitral
     award applicable to the Relevant Parties of which we have knowledge (after
     due inquiry) or (d) result in a breach of, constitute a default under,
     require any consent under, or result in the acceleration or required
     prepayment of any indebtedness pursuant to the terms of, any agreement or
     instrument of which we have knowledge to which any Relevant Party is a
     party or by which any of them is bound or to which any of them is subject,
     or (except for the Liens created pursuant to the Security Documents) result
     in the creation or imposition of any Lien upon any Property of any Relevant
     Party pursuant to, the terms of any such agreement or instrument.

        The foregoing opinions are subject to the following comments and
qualifications:

        (A)  The enforceability of Section 11.03 of the Amended Credit Agreement
     may be limited by (i) laws rendering unenforceable indemnification contrary
     to Federal or state securities laws and the public policy underlying such
     laws and (ii) laws limiting the enforceability of provisions exculpating or
     exempting a party, or requiring indemnification of a party for, liability
     for its own action or inaction, to the extent the action or inaction
     involves gross negligence, recklessness, willful misconduct or unlawful
     conduct.

        (B)  The enforceability of provisions in the Credit Documents to the
     effect that terms may not be waived or modified except in writing may be
     limited under certain circumstances.

        (C)  We express no opinion as to (i) the effect of the laws of any
     jurisdiction in which any Lender is located (other than the State of New
     York) that limit the interest, fees or other charges such Lender may
     impose, (ii) Section 4.07(c) of the Credit Agreement, (iii) the second
     sentence of Section 11.10 of the Credit Agreement (and any similar
     provisions in any of the other Credit Documents), insofar as such sentence
     relates to the subject matter jurisdiction of the United States District
     Court for the Southern District of New York to adjudicate any controversy
     related to any of the Credit Documents and (iv) the applicability to the
     obligations of the Subsidiary Guarantors (or


                      Opinion of Counsel to the Obligors
                      ----------------------------------
<PAGE>
 
                                      -5-


     the enforceability of such obligations) of Section 548 of the Bankruptcy
     Code, Article 10 of the New York Debtor Creditor Law, or any provision of
     law relating to fraudulent conveyances, transfers or obligations.

          We express no opinion (a) as to the, and the effect of, compliance or
non-compliance by the Lenders or the Administrative Agent with any law, rule or
regulation applicable because of the legal or regulatory status or the specific
nature of the business of such Lender or Administrative Agent and (b) regarding
any law, rule or regulation to which any of the Relevant Parties may be subject,
or any approval which any of the Relevant Parties may be required to obtain,
because of the legal or regulatory status of the Lenders or the Administrative
Agent or because of any facts specifically pertaining to the Lenders or the
Administrative Agent.

          Our opinions are limited to the specific issues addressed and are
limited in all respects to laws and facts existing on the date hereof. By
rendering our opinions, we do not undertake to advise you of any changes in such
laws or facts which may occur after the date hereof.

          The foregoing opinions are limited to matters involving the Federal
laws of the United States, the Delaware General Corporation Law, the Delaware
Limited Liability Company Act and the law of the State of New York, and we do
not express any opinion as to the laws of any other jurisdiction (nor do we
express any opinion as to the applicability to, or the effect upon, the
transactions contemplated by the Credit Documents of the Federal Communications
Act of 1934, as amended, and the rules and regulations promulgated thereunder or
the policies of the FCC).

                      Opinion of Counsel to the Obligors
                      ----------------------------------
<PAGE>
 
                                      -6-


          At the request of our clients, this opinion letter is, pursuant to
Section 5(iii)(c) of Amendment No. 4, provided to you by us in our capacity as
counsel to the Relevant Parties and may not be relied upon by any Person for any
purpose other than in connection with the transactions contemplated by the
Amended Credit Agreement without, in each instance, our prior written consent.

                                          Very truly yours,



                                          [COOPERMAN LEVITT WINIKOFF
                                           LESTER & NEWMAN, P.C.]

                                          By:_______________________


                      Opinion of Counsel to the Obligors
                      ----------------------------------
<PAGE>
 
                                      -1-

                                                                       EXHIBIT B


             [Form of Opinion of Special New York Counsel to Chase]

                                                  _______, 1999


To the Lenders party to Amendment
No. 4 to the Credit Agreement referred to
below and The Chase Manhattan
Bank, as Administrative Agent

Ladies and Gentlemen:

  We have acted as special New York counsel to The Chase Manhattan Bank
                                                                       
("Chase") in connection with (i) the Second Amended and Restated Credit
  -----                                                                
Agreement dated as of June 24, 1997 (the "Credit Agreement") between Mediacom
                                          ----------------                   
California LLC ("Mediacom California"), Mediacom Delaware LLC ("Mediacom
                 -------------------                            --------
Delaware"), Mediacom Arizona LLC ("Mediacom Arizona" and, together with Mediacom
--------                           ----------------                             
California and Mediacom Delaware, the "Borrowers"), the lenders party thereto,
                                       ---------                              
Chase, as Administrative Agent, and First Union National Bank, as Documentation
Agent, providing for loans to be made by said lenders to the Borrowers in an
aggregate principal amount not exceeding $100,000,000, (ii) Amendment No. 4
thereto dated as of January 26, 1999 and (ii) the various other agreements,
instruments and other documents referred to in the next following paragraph.
Terms defined in Amendment No. 4 (including terms incorporated by reference into
Amendment No. 4) are used herein as defined therein; in addition, the Credit
Agreement as amended by Amendment No. 4 is referred to herein as the "Amended
                                                                      -------
Credit Agreement".  This opinion letter is being delivered pursuant to Section
----------------                                                              
5(iii)(d) of Amendment No. 4.

  In rendering the opinions expressed below, we have examined the following
agreements, instruments and other documents:

  (a)  the Credit Agreement;

  (b)  Amendment No. 4; and

  (c)  the New Notes being executed and delivered to the Lenders on the
       date hereof (collectively, the "New Notes").
                                       ---------   

                          Opinion of Counsel to Chase
                          ---------------------------
<PAGE>
 
                                      -2-

Amendment No. 4, the Amended Credit Agreement, the New Notes and the
Confirmation and Consent are collectively referred to as the "Credit Documents";
                                                              ----------------  
the Borrowers, Mediacom and the Manager are herein collectively referred to as
the "Relevant Parties".
     ----------------  

          In our examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals and the
conformity with authentic original documents of all documents submitted to us as
copies. When relevant facts were not independently established, we have relied
upon representations made in or pursuant to Amendment No. 4 and the Amended
Credit Agreement.

          In rendering the opinions expressed below, we have assumed, with
respect to all of the documents referred to in this opinion letter, that:

          (i)   such documents have been duly authorized by, have been duly
                executed and delivered by, and (except to the extent set forth
                in the opinions below as to the Borrowers) constitute legal,
                valid, binding and enforceable obligations of, all of the
                parties to such documents;

          (ii)  all signatories to such documents have been duly authorized; and

          (iii) all of the parties to such documents are duly organized and
                validly existing and have the power and authority (corporate or
                other) to execute, deliver and perform such documents.

          Based upon and subject to the foregoing and subject also to the
comments and qualifications set forth below, and having considered such
questions of law as we have deemed necessary as a basis for the opinions
expressed below, we are of the opinion that each of Amendment No. 4 and the
Amended Credit Agreement constitutes the legal, valid and binding obligation of
each Relevant Party party thereto, enforceable against such Relevant Party in
accordance with its terms, except as may be limited by bankruptcy, insolvency,
reorganization, moratorium or other similar laws relating to or affecting the
rights of creditors generally and except as the enforceability of Amendment No.
4 or the Amended Credit Agreement is subject to the application of general
principles of equity (regardless of whether considered in a proceeding in equity
or at law), including, without limitation, (a) the possible unavailability of
specific performance, injunctive relief or any other equitable remedy and (b)
concepts of materiality, reasonableness, good faith and fair dealing.

          The foregoing opinions are subject to the following comments and
qualifications:

          (A)  The enforceability of Section 11.03 of the Amended Credit
     Agreement may be limited by (i) laws rendering unenforceable
     indemnification contrary to Federal or state securities laws and the public
     policy underlying such laws and (ii) laws limiting the


                          Opinion of Counsel to Chase
                          ---------------------------
<PAGE>
 
                                      -3-

     enforceability of provisions exculpating or exempting a party, or requiring
     indemnification of a party for, liability for its own action or inaction,
     to the extent the action or inaction involves gross negligence,
     recklessness, willful misconduct or unlawful conduct.

          (B)  The enforceability of provisions in the Credit Documents to the
     effect that terms may not be waived or modified except in writing may be
     limited under certain circumstances.

          (C)  We express no opinion as to (i) the effect of the laws of any
     jurisdiction in which any Lender is located (other than the State of New
     York) that limit the interest, fees or other charges such Lender may
     impose, (ii) Section 4.07(c) of the Amended Credit Agreement, and (iii) the
     second sentence of Section 11.10 of the Amended Credit Agreement, insofar
     as such sentence relates to the subject matter jurisdiction of the United
     States District Court for the Southern District of New York to adjudicate
     any controversy related to the Credit Documents and (iv) the applicability
     to the obligations of the Subsidiary Guarantors (or the enforceability of
     such obligations) of Section 548 of the Bankruptcy Code, Article 10 of the
     New York Debtor Creditor Law, or any provision of law relating to
     fraudulent conveyances, transfers or obligations.
 
          The foregoing opinions are limited to matters involving the Federal
laws of the United States and the law of the State of New York, and we do not
express any opinion as to the laws of any other jurisdiction (nor do we express
any opinion as to the applicability to, or the effect upon, the transactions
contemplated by the Credit Documents of the Federal Communications Act of 1934,
as amended, the rules and regulations promulgated thereunder or the policies of
the FCC).

          At the request of our client, this opinion letter is, pursuant to
Section 5(iii)(d) of Amendment No. 4, provided to you by us in our capacity as
special New York counsel to Chase and may not be relied upon by any Person for
any purpose other than in connection with the transactions contemplated by the
Amended Credit Agreement without, in each instance, our prior written consent.

                                          Very truly yours,


RJW/___


                          Opinion of Counsel to Chase
                          ---------------------------