Certifications of Chief Executive Officer and Co-Chief Financial Officers of
         Comcast Corporation pursuant to Section 1350 of Chapter 63 of
                       Title 18 of the United States Code


      Brian L. Roberts, Chief Executive Officer, Lawrence S. Smith, Co-Chief
Financial Officer and John R. Alchin, Co-Chief Financial Officer, of Comcast
Corporation, each certifies that, to the best of his knowledge:

     1.   the Comcast Corporation Quarterly Report on Form 10-Q for the quarter
          ended June 30, 2002 (the "Report") fully complies with the
          requirements of Section 13(a) or 15(d) of the Securities Exchange Act
          of 1934; and

     2.   the information contained in the Report fairly presents, in all
          material respects, the financial condition and results of operations
          of Comcast Corporation.


                                            /s/ Brian L. Roberts
                                            ------------------------------------
                                            Name: Brian L. Roberts
                                            Chief Executive Officer


                                            /s/ Lawrence S. Smith
                                            ------------------------------------
                                            Name:  Lawrence S. Smith
                                            Co-Chief Financial Officer


                                            /s/ John R. Alchin
                                            ------------------------------------
                                            Name:  John R. Alchin
                                            Co-Chief Financial Officer