**Exhibit 31.1**

**CERTIFICATION UNDER SECTION 302 OFTHE SARBANES-OXLEY ACT OF 2002**

I, Robert E. Conway, Chief Executive Officer,certify that:

1. I have reviewed this annual report on Form10-K of Array BioPharma Inc.;

2. Based on my knowledge, this report does notcontain any untrue statement of a material fact or omit to state a materialfact necessary to make the statements made, in light of the circumstances underwhich such statements were made, not misleading with respect to the periodcovered by this report;

3. Based on my knowledge, the financialstatements, and other financial information included in this report, fairlypresent in all material respects the financial condition, results of operationsand cash flows of the registrant as of, and for, the periods presented in thisreport;

4. The registrant’s other certifying officer andI are responsible for establishing and maintaining disclosure controls andprocedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) andinternal control over financial reporting (as defined in Exchange Act Rules13a-15(f) and 15d-15(f)) for the registrant and have:

a) Designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designedunder our supervision, to ensure that material information relating to theregistrant is made known to us by others within this entity, particularlyduring the period in which this report is being prepared;

b) Designed such internal control over financial reporting, or causedsuch internal control over financial reporting to be designed under oursupervision, to provide reasonable assurance regarding the reliability offinancial reporting and the preparation of financial statements for externalpurposes in accordance with generally accepted accounting principles;

c) Evaluated the effectiveness of the registrant’s disclosure controlsand procedures and presented in this report our conclusions about theeffectiveness of the disclosure controls and procedures, as of the end of theperiod covered by this report based on such evaluation; and

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

5. The registrant’s other certifying officer andI have disclosed, based on our most recent evaluation of internal control overfinancial reporting, to the registrant’s auditors and the audit committee ofregistrant’s board of directors (or persons performing the equivalentfunctions):

(a)          Allsignificant deficiencies and material weaknesses in the design or operation ofinternal control over financial reporting which are reasonably likely toadversely affect the registrant’s ability to record, process, summarize andreport financial information; and

(b)         Anyfraud, whether or not material, that involves management or other employees whohave a significant role in the registrant’s internal control over financialreporting.
| Date: September  12, 2007 |   | /s/ Robert E.  Conway   |   |
|---------------------------|--------|-------------------------|--------|
|                      |   |                    |
|                      |   | Robert E. Conway        |
|                      |   | Chief Executive Officer |

 

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