# **Exhibit 31.1**

# ** **

# **CERTIFICATION**

 

I, Raymond I.Wilcox, certify that:

 

1.               I have reviewedthis Annual Report on Form 10-K/A of Chevron Phillips Chemical Company LLC;

 

2.               Based on myknowledge, this report does not contain any untrue statement of a material factor omit to state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

 

3.               Based on myknowledge, the financial statements, and other financial information includedin 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.               The registrant’sother certifying 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)) 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 materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared;

 

b)             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

 

c)              Disclosed in thisreport any change in the registrant’s internal control over financial reporting(as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) that occurred duringthe registrant’s most recent fiscal quarter (the registrant’s fourth fiscalquarter in the case of an annual report) that has materially affected, or isreasonably likely to materially affect, the registrant’s internal control overfinancial reporting; and

 

5.               The registrant’s other certifying officerand I have disclosed, based on our most recent evaluation of internal controlover financial reporting, to the registrant’s auditors and the audit committeeof registrant’s board of directors (or persons performing the equivalentfunctions):

 

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 3, 2006 | * * | * * | */s/**Raymond I. Wilcox*              |
|----------------------|----------|----------|---------------------------------------|
|                 |     |     | Raymond I.  Wilcox                    |
|                 |     |     | President and Chief Executive Officer |

 

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