================================================================================
                                  UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                 SCHEDULE 13D/A

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934
                                (AMENDMENT NO. 3)

                               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

                                  APRIL 7, 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 PRIVATE 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
--------------------------------------------------------------------------------
             7
                  SOLE VOTING POWER
NUMBER OF
                          -0-
 SHARES      -------------------------------------------------------------------
             8
BENEFICIALLY      SHARED VOTING POWER
                    58,835,185*
 OWNED BY    -------------------------------------------------------------------
             9
  EACH            SOLE DISPOSITIVE POWER
                           -0-
REPORTING    -------------------------------------------------------------------
             10
PERSON WITH       SHARED DISPOSITIVE POWER
                      58,835,185*
--------------------------------------------------------------------------------
            11    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                      58,835,185*

--------------------------------------------------------------------------------
            12    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
                  SHARES    [ ]
--------------------------------------------------------------------------------
            13    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                      7.6%**
--------------------------------------------------------------------------------
            14    TYPE OF REPORTING PERSON
                      PN
--------------------------------------------------------------------------------




___________________
*   Assumes the full conversion of the Convertible Subordinated Notes
    beneficially owned by the Investors in accordance with their terms.

**  Represents the percentage of Class A Common Stock beneficially owned by WP
    VIII as of April 7, 2003 assuming full conversion of the Convertible
    Subordinated Notes beneficially owned by the Investors in accordance with
    their terms. Based on the same assumption, as of April 7, 2003, WP VIII
    beneficially owned 3.5% 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
--------------------------------------------------------------------------------
             7
                  SOLE VOTING POWER
NUMBER OF
                          -0-
 SHARES      -------------------------------------------------------------------
             8
BENEFICIALLY      SHARED VOTING POWER
                    58,835,185*
 OWNED BY    -------------------------------------------------------------------
             9
  EACH            SOLE DISPOSITIVE POWER
                           -0-
REPORTING    -------------------------------------------------------------------
             10
PERSON WITH       SHARED DISPOSITIVE POWER
                      58,835,185*
--------------------------------------------------------------------------------
            11    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                      58,835,185*

--------------------------------------------------------------------------------
            12    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
                  SHARES                                                     [ ]
--------------------------------------------------------------------------------
            13    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                      7.6%**
--------------------------------------------------------------------------------
            14    TYPE OF REPORTING PERSON
                      PN
--------------------------------------------------------------------------------




___________________
*   Assumes the full conversion of the Convertible Subordinated Notes
    beneficially owned by the Investors in accordance with their terms.

**  Represents the percentage of Class A Common Stock beneficially owned by WP
    as of April 7, 2003 assuming full conversion of the Convertible Subordinated
    Notes beneficially owned by the Investors in accordance with their terms.
    Based on the same assumption, as of April 7, 2003, WP beneficially owned
    3.5% 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
--------------------------------------------------------------------------------
             7
                  SOLE VOTING POWER
NUMBER OF
                          -0-
 SHARES      -------------------------------------------------------------------
             8
BENEFICIALLY      SHARED VOTING POWER
                    58,835,185*
 OWNED BY    -------------------------------------------------------------------
             9
  EACH            SOLE DISPOSITIVE POWER
                           -0-
REPORTING    -------------------------------------------------------------------
             10
PERSON WITH       SHARED DISPOSITIVE POWER
                      58,835,185*
--------------------------------------------------------------------------------
            11    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                      58,835,185*

--------------------------------------------------------------------------------
            12    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
                  SHARES                                                     [ ]
--------------------------------------------------------------------------------
            13    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                      7.6%**
--------------------------------------------------------------------------------
            14    TYPE OF REPORTING PERSON
                      OO
--------------------------------------------------------------------------------




___________________
*   Assumes the full conversion of the Convertible Subordinated Notes
    beneficially owned by the Investors in accordance with their terms.

**  Represents the percentage of Class A Common Stock beneficially owned by WP
    LLC as of April 7, 2003 assuming full conversion of the Convertible
    Subordinated Notes beneficially owned by the Investors in accordance with
    their terms. Based on the same assumption, as of April 7, 2003, WP LLC
    beneficially owned 3.5% of the outstanding Class A Common Stock and Class B
    Common Stock, taken as a whole.

                                      -4-



                               AMENDMENT NO. 3 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 and Amendment No. 2 thereto
filed October 17, 2002 (as so amended, the "Schedule 13D") on behalf 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. 3 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 and restated to read as follows:

(a)   The Reporting Persons beneficially own shares of Class A Common Stock by
      virtue of the Investors' beneficial ownership of shares of Class A Common
      Stock and of the Issuer's 6.5% Convertible Subordinated Notes due 2009
      (the "Convertible Subordinated Notes"), which are convertible at the
      option of the holder into 330.75 shares of Class A Common Stock per $1,000
      principal amount of Convertible Subordinated Notes, subject to adjustment
      in certain circumstances. As of April 7, 2003, the Reporting Persons
      beneficially owned an aggregate of 58,835,185 shares of Class A Common
      Stock, representing 33,650,000 shares of Class A Common Stock beneficially
      owned by the Investors and 25,185,185 shares of Class A Common Stock that
      may be acquired by the Investors upon full conversion of the Convertible
      Subordinated Notes beneficially owned by the Investors. Of the aggregate
      of 58,835,185 shares of Class A Common Stock beneficially owned by WP and
      WP LLC, approximately 1,770,939 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.

      Assuming full conversion of the Convertible Subordinated Notes
      beneficially owned by the Investors, as of April 7, 2003, the 58,835,185
      shares of Class A Common Stock beneficially owned by each Reporting Person
      represented approximately 7.6% of the outstanding shares of Class A Common
      Stock, and 3.5% 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, in each case, after giving effect to the
      issuance of the Class A Common Stock upon full conversion of the
      Convertible Subordinated Notes beneficially owned by the Investors (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).

                                      -5-


(b)   As described in paragraph (a) above, the Group Members have beneficial
      ownership over an aggregate of 58,835,185 shares of Class A Common Stock.
      Of this aggregate of 58,835,185 shares of Class A Common Stock, 33,650,000
      shares are represented by the shares of Class A Common Stock beneficially
      owned by the Investors and 25,185,185 are represented by shares of Class A
      Common Stock that are issuable to the Investors upon full conversion of
      the Convertible Subordinated Notes beneficially owned by the Investors.
      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 $34,900,000 in brokered transactions as described
      below:



                Date             Aggregate Principal      Price (% of Principal     Gross Proceeds (not including
                                       Amount                    Amount)                  accrued interest)
        ------------------       ------------------        -------------------     ------------------------
                                                                                  
               3/3/03                $2,000,000                   91.50%                      $1,830,000
               3/6/03                  $500,000                   91.50%                        $457,500
               3/7/03                $1,000,000                   91.50%                        $915,000
              3/14/03                $7,000,000                   91.50%                      $6,405,000
              3/17/03                $2,500,000                   91.50%                      $2,287,500
              3/18/03                $2,000,000                   91.50%                      $1,830,000
              3/21/03                  $500,000                   92.50%                        $462,500
              3/25/03                $3,500,000                   92.79%                      $3,247,500
              3/26/03                $3,500,000                   93.25%                      $3,263,750
              3/28/03                $5,000,000                   93.00%                      $4,650,000
               4/7/03                $7,400,000                   93.85%                      $6,944,493


      Except as described herein, during the last sixty days there were 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)   Not applicable.

                                      -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:  April 7, 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-