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 Plaza





Chief
      Executive Officer





September
      13, 2007