**Exhibit 31.1**

I, Scott A. Montgomery, certify that:

1. I have reviewed thisquarterly report on Form 10-QSB of National Mercantile Bancorp;

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,results of operations and cash flows of the small business issuer as of, andfor, the periods presented in this report;

4. The small business issuer’sother certifying officer(s) and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in Exchange ActRules 13a-15(e) and 15d-15(e)) for the small business issuer and have:

(a) Designed such disclosurecontrols and procedures, or caused such disclosure controls and procedures tobe designed under our supervision, to ensure that material information relatingto the small business issuer, including its consolidated subsidiaries, is madeknown to us by others within those entities, particularly during the period inwhich this report is being prepared;

 (b) Evaluated the effectiveness of the smallbusiness issuer’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

(c) Disclosed in this reportany change in the small business issuer’s internal control over financialreporting that occurred during the small business issuer’s most recent fiscalquarter (the small business issuer’s fourth fiscal quarter in the case of anannual report) that has materially affected, or is reasonably likely tomaterially affect, the small business issuer’s internal control over financialreporting; and

5.  The small businessissuer’s other certifying officer(s) and I have disclosed, based on our mostrecent evaluation of internal control over financial reporting, to the smallbusiness issuer’s auditors and the audit committee of the small business issuer’sboard of directors (or persons performing the equivalent functions):

(a) All significantdeficiencies and material weaknesses in the design or operation of internalcontrol over financial reporting which are reasonably likely to adverselyaffect the small business issuer’s ability to record, process, summarize andreport financial information; and

(b) Any fraud, whether ornot material, that involves management or other employees who have asignificant role in the small business issuer’s internal control over financialreporting.
| Date:  | October 4, 2006 |                     |   | /s/ SCOTT A. MONTGOMERY |   |   |
|--------|-----------------|--------------------------|--------|-------------------------|--------|--------|
|   |            | Scott A.  Montgomery     |   |                    |
|   |            | Chief Executive  Officer |   |                    |

 

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