Exhibit  21

Agere
Subsidiaries

|Domestic (U.S.) Companies                     |  | Jurisdiction ofOrganization | 
|--------------------------------------------- |  | --------------------------- | 
|                                              |  |                             | 
|Agere Systems American Parkway, L.P.          |  | Delaware                    | 
|Agere Systems Asia Pacific Inc.               |  | Delaware                    | 
|Agere Systems EMEA Inc.                       |  | Delaware                    | 
|Agere Systems Holdings Inc.                   |  | Delaware                    | 
|Agere Systems International LLC               |  | Delaware                    | 
|Agere Systems LVCC LLC                        |  | Delaware                    | 
|Agere Systems Management Services Inc.        |  | Delaware                    | 
|Agere Systems Receivables Funding LLC         |  | Delaware                    | 
|Enable Semiconductor Inc.                     |  | California                  | 
|Massana Inc.                                  |  | Delaware                    | 
|Mustang Acquisition Corp.                     |  | Delaware                    | 
|Optical Insurance Co.                         |  | Vermont                     | 
|Agere Systems Opto West Inc.                  |  | Delaware                    | 
|Foreign Companies                             | 
|Agere Systems Australia Pty Ltd.              |  | Australia                   | 
|Agere Systems (Shanghai) Co. Ltd.             |  | China                       | 
|Agere Systems Trading (Shanghai) Co., Ltd.    |  | China                       | 
|Agere Systems Canada Corp.                    |  | Canada                      | 
|Agere Systems Deutschland GmbH & Co. KG       |  | Germany                     | 
|Agere Systems Deutschland Verwaltungs GmbH    |  | Germany                     | 
|Agere Systems Espana SL                       |  | Spain                       | 
|Agere Systems Hong Kong Ltd.                  |  | Hong Kong                   | 
|Agere Systems India Pvt. Ltd.                 |  | India                       | 
|Agere Systems Japan Ltd.                      |  | Japan                       | 
|Agere Systems Korea Ltd.                      |  | Korea                       | 
|Agere Systems Limited                         |  | U.K.                        | 
|Agere Systems Management S.L                  |  | Spain                       | 
|Agere Systems Microelectronics (Thai) Ltd.    |  | Thailand                    | 
|Agere Systems Nederland B.V                   |  | Netherlands                 | 
|Agere Systems Singapore Pte. Ltd.             |  | Singapore                   | 
|Agere Systems Investments Pte. Ltd.           |  | Singapore                   | 
|Agere Systems (Ireland) Limited               |  | Ireland                     | 
|Agere Systems (Ireland) Design Limited        |  | Ireland                     | 
|Agere Systems (Ireland) Research Limited      |  | Ireland                     | 
|Agere Systems (Ireland) International Limited |  | Ireland                     | 
|Agere Systems (Spain) Technologies S.L        |  | Spain                       | 
|Optimay GmbH                                  |  | Germany                     |