**EXHIBIT 31.1**

 

**CERTIFICATION**

 

I,Peter A. Dea, certify that:

 

1.               Ihave reviewed this quarterly report on Form 10-Q of Western Gas Resources,Inc.;

 

2.               Basedon my knowledge, this report does not contain any untrue statement of amaterial fact or omit to state a material fact necessary to make the statementsmade, in light of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

 

3.               Basedon my knowledge, the financial statements, and other financial informationincluded in this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the registrant as of, andfor, the periods presented in this report;

 

4.               Theregistrant’s other certifying officer and I are responsible for establishingand maintaining disclosure controls and procedures (as defined in Exchange ActRules 13a-15(e) and 15d-15(e)) and internal control over financialreporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for theregistrant and have:

 

(a)               Designed such disclosure controlsand procedures, or caused such disclosure controls and procedures to bedesigned under our supervision, to ensure that material information relating tothe registrant, including its consolidated subsidiaries, is made known to us byothers within those entities, particularly during the period in which thisreport is being prepared;

 

(b)               Designed such internal controlover financial reporting, or caused such internal control over financialreporting to be designed under our supervision, to provide reasonable assuranceregarding the reliability of financial reporting and the preparation offinancial statements for external purposes in accordance with generallyaccepted accounting principles;

 

(c)               Evaluated the effectiveness ofthe registrant’s disclosure controls and procedures and presented in thisreport our conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on suchevaluation; and

 

(d)               Disclosed in this report anychange in the registrant’s internal control over financial reporting thatoccurred during the registrant’s most recent fiscal quarter  (the registrant’s fourth fiscal quarter inthe case of an annual report) that has materially affected, or is reasonablylikely to materially affect, the registrant’s internal control over financialreporting; and

 

5.               Theregistrant’s other certifying officer and I have disclosed, based on our mostrecent evaluation of internal control over financial reporting, to theregistrant’s auditors and the audit committee of registrant’s board ofdirectors (or persons performing the equivalent function):

 

(a)               All significant deficiencies andmaterial weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect theregistrant’s ability to record, process, summarize and report financialinformation; and

 

(b)               Any fraud, whether or notmaterial, that involves management or other employees who have a significantrole in the registrant’s internal control over financial reporting.

 

Dated:May 9, 2006

 
|   | /s/  Peter A. Dea                      |   |
|--------|----------------------------------------|--------|
|   | Peter  A. Dea                          |
|   | President  and Chief Executive Officer |

 

----