==============================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                 SCHEDULE 13D/A

                    Under the Securities Exchange Act of 1934
                                (Amendment No. 5)

                               Agere Systems Inc.
           ---------------------------------------------------------
                                (Name of Issuer)

                 Class A Common Stock, par value $0.01 per share
                         (Title of Class of Securities)

                                   00845V 10 0
               -------------------------------------------------
                                 (CUSIP Number)
       ------------------------------------------------------------------

                                Scott A. Arenare
                      Managing Director and General Counsel
                               Warburg Pincus LLC
                              466 Lexington Avenue
                            New York, New York 10017
                                 (212) 878-0600
       ------------------------------------------------------------------
            (Name, Address and Telephone Number of Person Authorized
                     to Receive Notices and Communications)

                                 With a copy to:
                              Andrew R. Brownstein
                         Wachtell, Lipton, Rosen & Katz
                               51 West 52nd Street
                            New York, New York 10019
                                 (212) 403-1000


                                   May 2, 2003
       ------------------------------------------------------------------
             (Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of ss.ss. 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the
following box: [ ].

                                Page 1 of 8 Pages

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   1          NAME OF REPORTING PERSON
              I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
                    WARBURG PINCUS EQUITY VIII, L.P.
                    I.R.S. IDENTIFICATION NO. 13-4161869
--------------------------------------------------------------------------------
   2          CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP        (a) [X]
                                                                      (b) [ ]
--------------------------------------------------------------------------------
   3          SEC USE ONLY                                        [ ]
--------------------------------------------------------------------------------
   4          SOURCE OF FUNDS
                    WC
--------------------------------------------------------------------------------
   5          CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
              PURSUANT TO ITEMS 2(d) OR 2(e)
                                                                          [ ]
--------------------------------------------------------------------------------
   6          CITIZENSHIP OR PLACE OF ORGANIZATION
                    DELAWARE
--------------------------------------------------------------------------------
   NUMBER OF               7.  SOLE VOTING POWER
                                     -0-
     SHARES
                    ------------------------------------------------------------
  BENEFICIALLY
                            8.  SHARED VOTING POWER
    OWNED BY                         33,650,000

      EACH          ------------------------------------------------------------
                            9.  SOLE DISPOSITIVE POWER
   REPORTING                         -0-

  PERSON WITH       ------------------------------------------------------------
                           10.  SHARED DISPOSITIVE POWER
                                     33,650,000

--------------------------------------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                    33,650,000
--------------------------------------------------------------------------------
     12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES                                                      [ ]
--------------------------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                    4.5%*
--------------------------------------------------------------------------------
     14       TYPE OF REPORTING PERSON
                    PN
--------------------------------------------------------------------------------







--------------------
* Represents the percentage of Class A Common Stock beneficially owned by WP
VIII as of May 2, 2003.  As of May 2, 2003, WP VIII beneficially owned 2.0% of
the outstanding Class A Common Stock and Class B Common Stock, taken as a whole.




--------------------------------------------------------------------------------
   1          NAME OF REPORTING PERSON
              I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
                    WARBURG PINCUS & CO.
                    I.R.S. IDENTIFICATION NO. 13-6358475
--------------------------------------------------------------------------------
   2          CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                     (a)  [X]
                                                                     (b)  [ ]
--------------------------------------------------------------------------------
   3          SEC USE ONLY
                                                                          [ ]
--------------------------------------------------------------------------------
   4          SOURCE OF FUNDS
                    WC
--------------------------------------------------------------------------------
   5          CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
              PURSUANT TO ITEMS 2(d) OR 2(e)
                                                                            [ ]
--------------------------------------------------------------------------------
   6          CITIZENSHIP OR PLACE OF ORGANIZATION
                    NEW YORK
--------------------------------------------------------------------------------
    NUMBER OF               7.  SOLE VOTING POWER
                                     -0-
     SHARES
                    ------------------------------------------------------------
  BENEFICIALLY
                            8.  SHARED VOTING POWER
    OWNED BY                         33,650,000

      EACH          ------------------------------------------------------------
                            9.  SOLE DISPOSITIVE POWER
   REPORTING                         -0-

  PERSON WITH       ------------------------------------------------------------
                           10.  SHARED DISPOSITIVE POWER
                                     33,650,000

--------------------------------------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                    33,650,000
--------------------------------------------------------------------------------
     12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES                                                       [ ]
--------------------------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                    4.5%*
--------------------------------------------------------------------------------
     14       TYPE OF REPORTING PERSON
                    PN
--------------------------------------------------------------------------------







--------------------
* Represents the percentage of Class A Common Stock beneficially owned by WP
as of May 2, 2003.  As of May 2, 2003, WP beneficially owned 2.0% of the
outstanding Class A Common Stock and Class B Common Stock, taken as a whole.

                                      -3-




--------------------------------------------------------------------------------
   1          NAME OF REPORTING PERSON
              I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
                    WARBURG PINCUS LLC
                    I.R.S. IDENTIFICATION NO. 13-3536050
--------------------------------------------------------------------------------
   2          CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [X]
                                                                    (b)  [ ]
--------------------------------------------------------------------------------
   3          SEC USE ONLY
                                                                         [ ]
--------------------------------------------------------------------------------
   4          SOURCE OF FUNDS
                    WC
--------------------------------------------------------------------------------
   5          CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
              PURSUANT TO ITEMS 2(d) OR 2(e)                             [ ]
--------------------------------------------------------------------------------
   6          CITIZENSHIP OR PLACE OF ORGANIZATION
                    NEW YORK
--------------------------------------------------------------------------------
    NUMBER OF               7.  SOLE VOTING POWER
                                     -0-
     SHARES
                    ------------------------------------------------------------
  BENEFICIALLY
                            8.  SHARED VOTING POWER
    OWNED BY                         33,650,000

      EACH          ------------------------------------------------------------
                            9.  SOLE DISPOSITIVE POWER
   REPORTING                         -0-

  PERSON WITH       ------------------------------------------------------------
                           10.  SHARED DISPOSITIVE POWER
                                     33,650,000

--------------------------------------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                    33,650,000
--------------------------------------------------------------------------------
     12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES                                                      [ ]
--------------------------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                    4.5%*
--------------------------------------------------------------------------------
     14       TYPE OF REPORTING PERSON
                    OO
--------------------------------------------------------------------------------







--------------------
*Represents the percentage of Class A Common Stock beneficially owned by WP LLC
as of May 2, 2003.  As of May 2, 2003, WP LLC beneficially owned 2.0% of the
outstanding Class A Common Stock and Class B Common Stock, taken as a whole.

                                      -4-




                               AMENDMENT NO. 5 TO
                                  SCHEDULE 13D

            Reference is made to the statement on Schedule 13D filed on June 21,
2002, Amendment No. 1 thereto filed July 29, 2002, Amendment No. 2 thereto filed
October 17, 2002, Amendment No. 3 thereto filed April 8, 2003 and Amendment No.
4 thereto filed April 30, 2003 (as so amended, the "Schedule 13D") on behalf of
Warburg Pincus Private Equity VIII, L.P., a limited partnership organized under
the laws of Delaware ("WP VIII"), Warburg Pincus & Co., a general partnership
organized under the laws of New York ("WP"), and Warburg Pincus LLC, a limited
liability company organized under the laws of New York ("WP LLC", and together
with WP VIII and WP, the "Reporting Persons"). All capitalized terms used
without definition herein have the meanings ascribed thereto in the Schedule
13D. This Amendment No. 5 to the Schedule 13D amends the Schedule 13D as
follows.

ITEM 5.     INTEREST IN SECURITIES OF THE ISSUER.

Item 5 of the Schedule 13D is amended as follows:

(a)  As of May 2, 2003, the Reporting Persons beneficially owned an aggregate of
     33,650,000 shares of Class A Common Stock. Of the aggregate of 33,650,000
     shares of Class A Common Stock beneficially owned by WP and WP LLC,
     approximately 1,039,785 shares represent shares of Class A Common Stock
     beneficially owned by WPNPE VIII I, WPNPE VIII II and WPGPE VIII. By reason
     of WP's and WP LLC's respective relationships with the Investors, under
     Rule 13d-3 of the Exchange Act, WP and WP LLC may be deemed to beneficially
     own all of the shares of Class A Common Stock that are beneficially owned
     by the Investors.

     As of May 2, 2003, the 33,650,000 shares of Class A Common Stock
     beneficially owned by each Reporting Person represented approximately 4.5%
     of the outstanding shares of Class A Common Stock, and 2.0% of the Issuer's
     outstanding shares of Class A Common Stock and Class B Common Stock, par
     value $0.01 per share (the "Class B Common Stock"), taken as a whole (based
     on 744,288,076 shares of Class A Common Stock and 907,995,677 shares of
     Class B Common Stock outstanding as of January 31, 2003, as set forth in
     the Issuer's Form 10-Q for the quarterly period ended December 31, 2002).

(b)  As described in paragraph (a) above, the Group Members have beneficial
     ownership over an aggregate of 33,650,000 shares of Class A Common Stock.
     Each of the Investors shares voting power and dispositive power over the
     shares of Class A Common Stock that such Investor beneficially owns with WP
     LLC and WP.

(c)  The Investors disposed of Convertible Subordinated Notes with an aggregate
     principal amount of $38,500,000 in brokered transactions as described
     below:


                                                                               

          Date          Aggregate Principal     Price (% of Principal         Gross Proceeds (not including
                              Amount                 Amount)                     accrued interest)
      ------------      -------------------     ---------------------         ------------------------------
        4/30/03             $8,000,000                  100%                           $8,000,000
         5/1/03            $10,000,000                101.88%                          $10,087,500
         5/2/03            $20,500,000                105.25%                          $21,576,250





                                      -5-



      Except as described herein, since the date of Amendment No. 4 to the
      Schedule 13D, there have been no transactions in shares of Class A Common
      Stock effected by the Reporting Persons or, to the best of their
      knowledge, by any of the persons set forth on Schedule I.

(d)  Except as set forth in this Item 5, no person other than each respective
     record owner referred to herein of the shares of Class A Common Stock is
     known to have the right to receive or the power to direct the receipt of
     dividends from, or the proceeds from the sale of, such shares of Class A
     Common Stock.

(e)  On May 2, 2003, each of the Reporting Persons ceased to be a beneficial
     owner or more than 5% of the Class A Common Stock.














                                      -6-




                                   SIGNATURES

            After reasonable inquiry and to the best of our knowledge and
belief, the undersigned certify that the information set forth in this statement
is true, complete and correct.

Dated:  May 5, 2003


                               WARBURG PINCUS PRIVATE EQUITY VIII, L.P.

                               By:  Warburg Pincus & Co.,
                                    General Partner

                                  By: /s/ Scott A. Arenare
                                     -----------------------------------------
                                        Name:  Scott A. Arenare
                                        Title: Partner


                               WARBURG PINCUS & CO.

                              By: /s/ Scott A. Arenare
                                  --------------------------------------------
                                  Name:  Scott A. Arenare
                                  Title: Partner


                               WARBURG PINCUS LLC

                              By: /s/ Scott A. Arenare
                                  ----------------------------------------------
                                  Name:  Scott A. Arenare
                                  Title: Member


                               WARBURG PINCUS NETHERLANDS PRIVATE EQUITY VIII
                                  C.V. I

                               By:  Warburg Pincus & Co.,
                                    General Partner

                                  By: /s/ Scott A. Arenare
                                     -----------------------------------------
                                        Name:  Scott A. Arenare
                                        Title: Partner


                                      -7-




                               WARBURG PINCUS NETHERLANDS PRIVATE EQUITY VIII
                                     C.V. II

                               By:  Warburg Pincus & Co.,
                                    General Partner

                                  By: /s/ Scott A. Arenare
                                     -----------------------------------------
                                        Name:  Scott A. Arenare
                                        Title: Partner


                               WARBURG PINCUS GERMANY PRIVATE EQUITY VIII KG

                               By:  Warburg Pincus & Co.,
                                    General Partner

                                  By: /s/ Scott A. Arenare
                                     -----------------------------------------
                                        Name:  Scott A. Arenare
                                        Title: Partner










                                      -8-