**EXHIBIT 31.1**

 

CERTIFICATIONS PURSUANT TO RULE 13a-14(a)

 

I, John J.Sullivan, Ph.D., certify that:

 

1.             I have reviewed this annual reporton Form 10-K of Mesa Laboratories, Inc.;

 

2.             Based on my knowledge, this reportdoes not contain any untrue statement of a material fact or omit to state amaterial 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, thefinancial statements, and other financial information included in this report,fairly present in all material respects the financial condition, results ofoperations and cash flows of the small business issuer as of, and for, theperiods presented in this report;

 

4.             The small business issuer’s othercertifying officer(s) and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-15(f)) for the small businessissuer and have:

 

(a) Designed such disclosure controls and procedures, or causedsuch disclosure controls and procedures to be designed under our supervision,to ensure that material information relating to the small business issuer,including its consolidated subsidiaries, is made known to us by others withinthose entities, particularly during the period in which this report is beingprepared;

 

(b) Designed such internal control over financial reporting, orcaused such 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 small business issuer’sdisclosure controls and procedures and presented in this report our conclusionsabout the effectiveness of the disclosure controls and procedures, as of theend of the period covered by this report based on such evaluation; and

 

(d) Disclosed in this report any change in the small businessissuer’s internal control over financial reporting that occurred during thesmall business issuer’s fourth fiscal quarter that has materially affected, oris reasonably likely to materially affect, the small business issuer’s internalcontrol over financial reporting; and

 

5.             The small business issuer’s othercertifying officer(s) and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to the small businessissuer’s auditors and the audit committee of the small business issuer’s boardof directors (or persons performing the equivalent functions):

 

(a) All significant deficiencies and material weaknesses in thedesign or operation of internal control over financial reporting which arereasonably likely to adversely affect the small business issuer’s ability torecord, process, summarize and report financial information; and

 

(b) Any fraud, whether or not material, that involves managementor other employees who have a significant role in the small business issuer’sinternal control over financial reporting.

 

 
| Date:  | July 13,  2009 |                     | /s/John J.  Sullivan, Ph.D. |
|--------|---------------------|--------------------------|-----------------------------|
|   |                |                     |
|   |                | John J.  Sullivan, Ph.D. |
|   |                | Chief Executive  Officer |

 

----