Exhibit
        31.1
 
 **CERTIFICATION**
 
 I,
        Elizabeth Plaza, certify that:
 
 1.
        I have
        reviewed this quarterly report on Form 10-QSB of Pharma-Bio Serv, Inc.
        ("Pharma-Bio Serv");
 
 2.
        Based
        on my knowledge, this quarterly 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 quarterly
        report;
 
 3.
        Based
        on my knowledge, the financial statements, and other financial information
        included in this quarterly report, fairly present in all material respects
        the
        financial condition, results of operations and cash flows of Pharma-Bio Serv
        as
        of and for, the periods presented in this quarterly report;
 
 4.
        Pharma-Bio Serv's other certifying officer and I are responsible for
        establishing and maintaining disclosure controls and procedures (as defined
        in
        Exchange Act Rules 13a-15(e) and 15(d)-15(e) for Pharma-Bio Serv 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 Pharma-Bio Serv, including its consolidated
        subsidiary, is made known to us by others within those entities, particularly
        during the period in which this quarterly report is being prepared;
 
 b.
        Evaluated the effectiveness of Pharma-Bio Serv'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
 
 c.
        Disclosed in this report any change in Pharma-Bio Serv's internal control
        over
        financial reporting that occurred during its most recent fiscal quarter
        (Pharma-Bio Serv's fourth fiscal quarter in the case of an annual report)
        that
        has materially affected, or is reasonably likely to materially affect,
        Pharma-Bio Serv's internal control over financial reporting.
 
 5.
        Pharma-Bio Serv's other certifying officer and I have disclosed, based on
        our
        most recent evaluation of internal control over financial reporting, to
        Pharma-Bio Serv's auditors and the audit committee of Pharma-Bio Serv'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 Pharma-Bio Serv'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 Pharma-Bio Serv's internal controls over financial
        reporting.
  /s/ Elizabeth
                PlazaElizabeth
                PlazaChief
                Executive
                OfficerMarch 16, 2007
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