AMENDMENT AGREEMENT
                           Dated as of August 19, 1999
             to the Compensation and Deferred Compensation Agreement
                between Comcast Corporation and Ralph J. Roberts
                as amended and restated effective August 30, 1998

         THIS AMENDMENT  AGREEMENT (the  "Amendment") is being made to amend the
provisions  of the  Compensation  and Deferred  Compensation  Agreement  between
Comcast  Corporation  and Ralph J.  Roberts (as amended and  restated  effective
August 30, 1998) (the "Compensation  Agreement") relating to the "Death Benefit"
provided in the Compensation Agreement.

         WHEREAS, Ralph J. Roberts ("Roberts") is the founder and Chairman of
the Board of Directors of Comcast Corporation (the "Company"), and they are
parties to the Compensation Agreement; and

         WHEREAS,  the Compensation  Agreement provides that, in lieu of certain
bonuses  which would  otherwise  have been payable by the Company upon  Roberts'
exercise of certain  options he held to purchase  shares of Class B Common Stock
of the Company in October 1998, Roberts' personal  representatives would receive
a lump-sum Death Benefit following Roberts' death; and

         WHEREAS,  the Death Benefit was intended to provide equivalent value to
the bonus rights  which were  eliminated  in  connection  with the  Compensation
Agreement, and

         WHEREAS,  Roberts'  willingness  to accept the Death Benefit in lieu of
the  terminated  bonus  rights  and to  exercise  his Class B  options  afforded
significant tax and accounting  benefits to the Company and required  Roberts to
incur significant current tax expense he would not otherwise have borne, and

         WHEREAS,  the  Subcommittee  on  Performance-Based  Compensation of the
Company's Board of Directors (the  "Subcommittee")  has determined that the base
Death Benefit should be increased by  $1,191,811,  to reflect tax costs incurred
by Roberts which were higher than expected when the Death Benefit was originally
calculated, and

         WHEREAS,  Roberts has proposed, and the Subcommittee has approved, that
Roberts be given an opportunity  to recommend  investments to the Company and to
have a portion of the Death Benefit reflect the results of such investments, and

         WHEREAS, the Subcommittee has determined that the present value cost to
the Company of the  proposal  made by Roberts does not exceed that of the simple
Death Benefit structure currently reflected in the Compensation  Agreement,  and
that the proposal includes adequate protection for the Company's interests,

         NOW THEREFORE, the parties agree as follows:

<PAGE>

         1. Section 3.11 of the Compensation Agreement is hereby amended and
restated in its entirety to read as follows:

            3.11 Supplemental Death Benefit.

                 (a) Death Benefit.  In addition to the other payments  provided
or referred to herein,  in the event of Roberts'  death  during the term of this
Agreement or thereafter the Company shall pay a supplemental  death benefit (the
"Death  Benefit")  as  calculated  herein to Roberts'  personal  representatives
within six (6) months following Roberts' date of death.

                 (b) Amount  and  Payment  of Death  Benefit.  The amount of the
Death  Benefit shall be the sum of the  following  amounts:  (i) the Base Amount
exclusive of the Aggregate  Initial  Variable  Account  Amount,  as each term is
respectively  defined  in (c) and  (d)(ii),  below,  plus (ii) the amount of the
Variable Account, as defined in (d)(i),  below, as of the close of business on a
business day selected by the Company that is within three  business  days of the
date on which payment is made to Roberts'  personal  representatives.  The Death
Benefit  shall be reduced if and to the extent  provided in (h)(i),  below.  The
Death Benefit,  less  applicable tax  withholding,  shall be paid in immediately
available funds,  except that the Company may, in its sole discretion,  elect to
pay all or any portion of the amount of the Variable Account by transfer in kind
to Roberts' personal  representatives of Company Investments (as defined herein)
valued at the value used for calculating the Death Benefit.

                 (c) Base  Portion  of  Death  Benefit.  The  "Base  Amount"  is
Thirty-One Million One Hundred Ninety-One  Thousand Eight Hundred Eleven Dollars
($31,191,811).

                 (d) Variable Portion of Death Benefit.  The "Variable Account,"
and the  "Aggregate  Initial  Variable  Account  Amount," shall be determined as
follows:

                     (i) At any time, and from time to time,  during the term of
                 his  employment by the Company  (whether as an employee or as a
                 consultant), Roberts may request that a specific portion of the
                 Base  Amount (up to, but not to exceed,  the full amount of the
                 Base Amount) be included in the Variable Account.  Such request
                 shall be made to the Company's Executive Vice President and the
                 Company's General Counsel (together, the "Company Officers") in
                 writing,  shall  specify  the amount so proposed to be added to
                 the Variable Account and a particular  investment or particular
                 investments,  each  of  which  is a  Qualified  Investment  (as
                 defined in (e), below),  in which the Company could invest such
                 amounts,  and  shall  certify  that,  to the  best of  Roberts'
                 knowledge,  each such  investment is a Qualified  Investment on
                 the date of such request or will be on the date the  investment
                 is made. The Company shall have complete discretion to grant or
                 to refuse Roberts'  request,  and shall grant Roberts'  request
                 only if it determines  (as provided  herein) that such proposed
                 investment is or will be a Qualified Investment.  The effective
                 date of any addition to the Variable Account shall be the later
                 of the date on which the Company grants Roberts' request or, in
                 the event the Company determines in its sole discretion to make
                 the  investment  proposed  by  Roberts  within  90  days of the
                 request, the date the Company makes such investment.


                                      -2-
<PAGE>

                     (ii) The Aggregate  Initial  Variable Account Amount is the
                 sum of all  amounts  transferred  to the  Variable  Account  as
                 provided  herein,  calculated  as of the date of transfer,  and
                 without  reflecting  any  gains,  losses,   expenses  or  other
                 transactions in the Variable Account.

                     (iii)  Upon  each  transfer  from  the Base  Amount  to the
                 Variable  Account,  each sum so transferred shall be associated
                 with  a  particular   Qualified  Investment  (which  may  be  a
                 hypothetical   investment   by  the   Company,   or  an  actual
                 investment, or any combination of the two, as determined by the
                 Company).  The amount of the Variable Account on any date shall
                 be  the  sum  of  the  fair  market  values  of  the  Qualified
                 Investments  associated with the Variable Account on such date,
                 less,  in the  event the  Aggregate  Initial  Variable  Account
                 Amount exceeds Twenty Million Four Hundred Twelve  Thousand One
                 Hundred Thirty-Seven Dollars  ($20,412,137),  compound interest
                 at eight  percent  (8%) per annum on the amount of such  excess
                 from the date such excess is created to the earlier of the date
                 on which the Variable Account is being valued or April 7, 2004.

                 (e)  Qualified  Investments.  A  "Qualified  Investment"  is an
investment  which is or would be  actually  available  to the  Company and which
would meet each of the following criteria if actually made by the Company at the
time  of the  initial  investment;  provided,  however,  that  the  Company  may
disapprove  of any such  investment  (or may  subsequently  cause any  Qualified
Investment  to be eliminated or disposed of) based,  in its  discretion,  on its
application of such criteria:

                     (i)  the  investment  can be made  without  any  actual  or
                 potential legal or regulatory restriction or negative impact on
                 the Company;

                     (ii)  the  investment   presents  no  actual  or  potential
                 conflict of  interest or  diversion  of  corporate  opportunity
                 between  Roberts  and the  Company or any  actual or  potential
                 conflict  of  interest  between  the  Company and the entity or
                 entities to which the investment relates;

                     (iii) the  investment  would not require  disclosure by the
                 Company in its financial statements as a business  relationship
                 or  transaction  with  management  or  a  related  party,  as a
                 compensation  committee  overlap  disclosure item, or otherwise
                 under Regulation S-K promulgated by the Securities and Exchange
                 Commission or Sections 13, 14 or 16 of the Securities  Exchange
                 Act  of  1934,  as  amended,   or  the   regulations  or  forms
                 thereunder;

                     (iv) the investment does not expose the Company to any risk
                 of loss or  mandatory  additional  investment  in excess of the
                 actual amount invested;

                     (v) the  investment  would at all times be  included on the
                 Company's audited financial  statements as an investment (or as
                 an offset to an accrued liability);



                                       -3-
<PAGE>

                     (vi) the investment is either  readily  marketable or there
                 is a reasonable means to dispose of the investment from time to
                 time (and no less frequently  than annually)  whether or not at
                 full value,  and there is reasonably  available any information
                 concerning the investment which the Company deems necessary for
                 effectuating the purposes of this Agreement; and

                     (vii) the investment is to be unencumbered and available to
                 satisfy the claims of general creditors of the Company.

                 (f) Variable Account - Company Investments and Other Rules.

                     (i) The Variable  Account  shall at all times be an account
                 on  the  books  of  the  Company  reflecting  the  hypothetical
                 investment of the Aggregate Initial Variable Account Amount and
                 the proceeds thereof in the specific Qualified Investments.

                     (ii) The Company shall reflect on the books of the Variable
                 Account  all  income,   gains,   losses,   and  other  proceeds
                 associated with the Qualified Investments therein. In the event
                 proceeds on a Qualified  Investment  are received in cash,  the
                 value of such cash shall be  included in the  Variable  Account
                 and, unless invested in another Qualified Investment,  shall be
                 deemed to have been invested in a special Qualified  Investment
                 on which interest accrues at the rate of eight percent (8%) per
                 annum from the date of investment until the earlier of the date
                 of  payment of the Death  Benefit  or April 7, 2004,  and which
                 thereafter does not pay interest.

                     (iii) If the Company makes actual investments corresponding
                 to any of such Qualified  Investments  (each such  investment a
                 "Company  Investment"),  (A) such Company  Investments shall be
                 part of the Company's general assets,  subject to the Company's
                 discretion  and  control,  and not  form  part of the  Variable
                 Account;  (B) Roberts shall have no right to obtain  possession
                 or  ownership of Company  Investments,  or to vote or otherwise
                 control them;  (C) the  transactions  reflected in the Variable
                 Account shall be the same as those with respect to such Company
                 Investments  (giving  regard  to any  difference  in  amount or
                 timing with respect to the Qualified Investment in the Variable
                 Account  and  such  Company  Investment);   (D)  the  Company's
                 out-of-pocket  costs in making,  maintaining,  and disposing of
                 each Company  Investment  shall be charged against the value of
                 the corresponding Qualified Investment in the Variable Account;
                 and (E) the Company shall have full discretion and control with
                 respect  to such  Company  Investments,  including  whether  to
                 retain or to sell or  otherwise  dispose  of such  investments;
                 provided,  that it shall exercise such discretion in good faith
                 with respect to Roberts. Nothing herein shall forbid Roberts to
                 consult with the Company  regarding  management  of any Company
                 Investments.

                     (iv) If at any time the Company determines,  as provided in
                 the first paragraph of (e), above, that an investment reflected
                 in the  Variable  Account is no longer a Qualified  Investment,
                 the Company shall promptly give Roberts written


                                      -4-
<PAGE>

                 notice of such  determination and the basis therefor,  and such
                 investment  shall be deemed sold at its then-fair market value.
                 Such sale shall be on the terms reflected in the  corresponding
                 sale, if any, of the appropriate  Company  Investment,  if any,
                 and otherwise shall be deemed to be for cash, with the proceeds
                 or such sale treated as described herein.  Nothing herein shall
                 require the sale or other  disposition of a Company  Investment
                 which is no longer a Qualified Investment.

                     (v) Roberts may request, from time to time, that all or any
                 portion  of  the  Variable  Account  be  transferred  from  the
                 then-current Qualifying  Investment(s) to one or more different
                 Qualified  Investments.  Such  request  shall be made,  and the
                 Company shall deal with such request, in the manner established
                 herein for initial  transfers to the Variable  Account,  except
                 that the Aggregate Initial Variable Account Amount shall not be
                 affected if any such request is granted.

                     (vi) In the event holders of an investment corresponding to
                 a  Qualified  Investment  are  required  to make an  investment
                 decision (e.g.,  acceptance or not of a tender offer;  exercise
                 of dissenter's rights),  and there is no corresponding  Company
                 Investment, the Company shall, after consultation with Roberts,
                 make a  determination  in good faith to reflect the actions the
                 Company determines a reasonable  investor would take and adjust
                 the  value  and   composition  of  such  Qualified   Investment
                 accordingly.

                 (g)  Procedures  and  Reports.  Except  as  otherwise  provided
herein,  all  determinations and waivers on the part of the Company with respect
to Qualified  Investments  shall be made jointly by the Company  Officers (after
such consultations with other management personnel,  the Subcommittee,  experts,
and Roberts, as they shall deem appropriate).  The Company shall provide Roberts
or his personal  representatives  and the  Subcommittee at the request of any of
them, but no less than once each calendar  year, a written report  regarding the
value of the Death  Benefit  as of a recent  date,  including  the value of each
Qualified Investment in the Variable Account and all transactions affecting such
value (including  interest,  dividends,  and  distributions  with respect to the
Qualified  Investments).  In the event  Roberts or his personal  representatives
disagree  with any such  valuation,  the  Company  and  Roberts or his  personal
representatives shall consult in good faith to resolve such disagreement, and if
such  disagreement  is  not so  resolved  the  appropriate  valuation  shall  be
determined by the Subcommittee under such reasonable procedures as it determines
at the time. The Company shall provide  Roberts or his personal  representatives
from time to time copies of all information received by the Company with respect
to Company Investments or the Qualified Investments in the Variable Account, and
shall promptly inform Roberts and the Subcommittee (in advance,  if possible) of
all transactions with respect to Company  Investments or which the Company deems
to affect the value of  Qualified  Investments.  The  Company  shall  notify the
Subcommittee in writing quarterly as to all amounts  transferred to the Variable
Account (including the Qualified Investment  associated with such amount) during
the  previous  calendar  quarter  and  any  changes  in the  composition  of the
Qualified Investments.


                                      -5-
<PAGE>

                 (h) Indemnification and Release.

                     (i) To the  extent of the  Death  Benefit,  Roberts  hereby
                 indemnifies the Company, and holds it harmless, against any and
                 all  liabilities,  costs,  and expenses  (including  reasonable
                 attorney  and  expert  fees),   including  without   limitation
                 indemnification  liabilities to officers,  directors, agents or
                 employees,  which arise in connection with Company  Investments
                 other than by reason of the bad faith,  willful misconduct,  or
                 gross   negligence  of  the  Company  or  such  persons.   Such
                 indemnification  shall be effected by charging the  appropriate
                 amount  against  the  relevant  Qualifying  Investment  in  the
                 Variable Account, and, to the extent of any excess, by reducing
                 any other component of the Death Benefit at the time or payment
                 thereof.

                     (ii) To the maximum extent permitted by law, Roberts hereby
                 releases  the  Company  and  each of its  officers,  directors,
                 agents,  and  employees,  from any and all liability to Roberts
                 arising out of the Company's  good-faith  management of Company
                 Investments, regardless of the effect of such management on the
                 value of the Death Benefit.

         2. All investments made by the Company at Roberts'  suggestion  through
February 22, 2000, as reported to the Subcommittee,  shall be considered to have
been made in  compliance  with Section 3.11 of the  Compensation  Agreement,  as
amended by this Amendment. As a result, each such investment shall be considered
a Company  Investment,  the  amount  of such  investment  (plus  any  associated
out-of-pocket  costs  incurred by the  Company)  shall be treated as part of the
Aggregate  Initial  Variable  Account  Amount as of such date, and the amount of
such investment shall be treated as part of the Variable Account associated with
a Qualified Investment identical to the Company Investment.

         3. This  Amendment  constitutes  the complete  agreement of the parties
regarding  the  Death  Benefit,   and   supersedes  all  prior   agreements  and
understandings.

         4. Except as amended hereby, the Compensation Agreement remains in full
force and effect.

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


                                               COMCAST CORPORATION
/s/ Ralph J. Roberts
Ralph J. Roberts

                                               By: /s/ Lawrence S. Smith
                                                     Lawrence S. Smith
                                                     Executive Vice President




                                      -6-