**Exhibit 31.1**

 

**Certification of Chairman andChief Executive Officer**

**Pursuant to Section 302 of theSarbanes-Oxley Act of 2002**

 

I, Allen Chao, Chairman and Chief Executive Officer, certify that:

 

1.             I have reviewed thisquarterly report on Form 10-Q of Watson Pharmaceuticals, Inc.;

 

2.             Based on my knowledge,this report does not contain any untrue statement of a material fact or omit tostate a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading withrespect to the period covered by this report;

 

3.             Based on my knowledge,the financial statements, and other financial information included in thisreport, fairly present in all material respects the financial condition, resultsof operations and cash flows of the registrant as of, and for, the periodspresented in this report;

 

4.             The registrant’s othercertifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e)and 15d-15(e)) and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

 

a)            designed suchdisclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision,  to ensure that material information relatingto the registrant, including its consolidated subsidiaries, is made known to usby others within those entities, particularly during the period in which thisreport is being prepared;

 

b)           designed such internalcontrol over financial reporting, or caused such internal control overfinancial reporting to be designed under our supervision, to provide reasonableassurance regarding the reliability of financial reporting and the preparationof financial statements for external purposes in accordance with generallyaccepted accounting principles;

 

c)            evaluated theeffectiveness of the registrant’s disclosure controls and procedures andpresented in this report our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of the period covered by thisreport based on such evaluation; and

 

d)           disclosed in this reportany change in the registrant’s internal control over financial reporting thatoccurred during the registrant’s most recent fiscal quarter (the registrant’sfourth fiscal quarter in the case of an annual report) that has materiallyaffected, or is reasonably likely to materially affect, the registrant’s internalcontrol over financial reporting; and

 

5.             The registrant’s othercertifying officer and I have disclosed, based on our most recent evaluation ofinternal control over financial reporting, to the registrant’s auditors and theaudit committee of the registrant’s board of directors (or persons performingthe equivalent function):

 

a)            all significantdeficiencies and material weaknesses in the design or operation of internalcontrol over financial reporting which are reasonably likely to adverselyaffect the registrant’s ability to record, process, summarize and reportfinancial information; and

 

b)           any fraud, whether ornot material, that involves management or other employees who have asignificant role in the registrant’s internal control over financial reporting.

 

Date:  August 9, 2005

 
|   | By:                                   | **/s/  Allen Chao** | ** ** |
|--------|---------------------------------------|---------------------|------------|
|   | Allen Chao, Ph.D.                     |                |
|   | Chairman and Chief  Executive Officer | ** **          |
|   | (Principal Executive  Officer)        | ** **          |

 

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