Exhibit
31.1





CERTIFICATION
OF PRINCIPAL EXECUTIVE OFFICER


PURSUANT
TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002





I,
Elizabeth Plaza, certify that:





1. I have reviewed this annual report on
Form 10-K of Pharma-Bio Serv Inc.;





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





3. Based on my knowledge, the financial
statements, and other financial information included in this report, fairly
present in all material respects the financial condition, results of operations
and cash flows of the registrant as of, and for, the periods presented in this
report;





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





a) Designed such disclosure controls and
procedures, or caused such disclosure controls and procedures to be designed
under our supervision, to ensure that material information relating to the
registrant, including its consolidated subsidiaries, is made known to us by
others within those entities, particularly during the period in which this
report is being prepared;





b) Designed such internal control over
financial reporting, or caused such internal control over financial reporting to
be designed under our supervision, to provide reasonable assurance regarding the
reliability of financial reporting and the preparation of financial statements
for external purposes in accordance with generally accepted accounting
principles;





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





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





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





a) All significant deficiencies and
material weaknesses in the design or operation of internal control over
financial reporting which are reasonably likely to adversely affect the
registrant’s ability to record, process, summarize and report financial
information; and





b) Any fraud, whether or not material,
that involves management or other employees who have a significant role in the
registrant’s internal control over financial reporting.




Date:
January 29, 2010




/s/
      Elizabeth PlazaElizabeth
      PlazaChief
      Executive Officer(principal
      executive officer)