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                                                                  Exhibit 10(ss)


                     FIRST AMENDMENT TO EMPLOYMENT AGREEMENT

         WHEREAS, Mel Karmazin (the "Executive") and Viacom Inc. ("Viacom")
entered into an employment agreement dated September 6, 1999 (the "Agreement")
to be effective at the Effective Time (as defined in the Agreement and Plan of
Merger between Viacom and CBS Corporation ("CBS") dated as of September 6, 1999,
as amended and restated as of October 8, 1999 and November 23, 1999 (as amended,
the "Merger Agreement")); and

         WHEREAS, the Executive and Viacom desire to amend the Agreement in
certain respects, as described hereinbelow;

         NOW, THEREFORE, the Executive and the Company agree that the Agreement
is hereby amended, effective as of September 6, 1999, as follows:

         1. Section 7(k) of the Agreement is amended hereby by adding a new
sentence at the end thereof to read as follows:

         "Notwithstanding anything hereinabove to the contrary, the provisions
         of this Section 7(k) shall not apply to any of the following: (i) any
         shares that were held in the Karmazin Charitable Lead Annuity Trust
         dated December 28, 1998 (the "Trust") on September 6, 1999 that are
         transferred from the Trust as required by the provisions of the trust
         agreement under which the Trust was established as in effect as of the
         date hereof ("Trust Agreement") and as may be required by the Internal
         Revenue Code of 1986, as amended (the "Code"), to the Mel Karmazin
         Foundation, Inc., a Delaware corporation (the "Foundation"), or to
         another

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         charitable organization, and any shares disposed of by the Foundation
         as required by the private foundation minimum distribution requirements
         of the Code, and the terms of the operative documents for such
         Foundation as in effect as of the date hereof (copies of which Trust
         and Foundation have been provided to Viacom by you); (ii) any shares
         required to be transferred by you to or for the benefit of your former
         spouse, Sharon Karmazin, pursuant to a Separation and Property
         Settlement Agreement dated as of July 1, 1996, as amended (the
         "Settlement Agreement") (a copy of which has been provided to Viacom by
         you); and (iii) any shares sold or disposed of (including pursuant to
         withholding by CBS or Viacom upon the exercise of stock options to
         acquire either CBS or Viacom shares) by you in order to satisfy any tax
         obligation arising upon your exercise of stock options (i) that would
         otherwise expire in accordance with their terms during the Employment
         Term within a reasonable period of time preceding such options'
         expiration or (ii) to satisfy any transfers of CBS or Viacom shares to
         Sharon Karmazin required pursuant to the Settlement Agreement."

         2. Except as hereinabove provided, the Agreement is ratified and
confirmed in all respects.

         IN WITNESS WHEREOF, the Executive and Viacom have executed this First
Amendment to the Agreement on this 31st day of December, 1999.

                                     VIACOM INC.

                                     by: /s/ Philippe P. Dauman
                                     -------------------------------------------
                                     Name: Philippe P. Dauman
                                     Title:  Deputy Chairman


ACCEPTED AND AGREED:


/s/ Mel Karmazin
------------------------------------
Mel Karmazin