EXHIBIT 99.12

               [CONSENT OF CREDIT SUISSE FIRST BOSTON CORPORATION]

             [LETTERHEAD OF CREDIT SUISSE FIRST BOSTON CORPORATION]



Board of Directors
AT&T Corp.
295 North Maple Avenue
Basking Ridge, New Jersey  07920

Members of the Board:

We hereby consent to the inclusion of our opinion letter to the Board of
Directors of AT&T Corp. ("AT&T") as Annex J to the Joint Proxy
Statement/Prospectus of AT&T and Comcast Corporation ("Comcast") included in the
Registration Statement on Form S-4 of AT&T Comcast Corporation relating to the
proposed merger transaction involving AT&T and Comcast and reference thereto in
such Joint Proxy Statement/Prospectus under the captions "CHAPTER ONE - SUMMARY
AND OVERVIEW OF THE TRANSACTIONS - Opinions of AT&T's Financial Advisors" and
"CHAPTER FOUR - OPINIONS OF FINANCIAL ADVISORS - Credit Suisse First Boston's
Opinion." In giving such consent, we do not admit that we come within the
category of persons whose consent is required under, and we do not admit that we
are "experts" for purposes of, the Securities Act of 1933, as amended, and the
rules and regulations promulgated thereunder.


                     /s/ Credit Suisse First Boston Corporation
                     ------------------------------------------
                     CREDIT SUISSE FIRST BOSTON CORPORATION

February 11, 2002