**Exhibit
31(a)**





**CERTIFICATION**





I, Randal
J. Kirk, certify that:





1.
    I
      have reviewed this Quarterly Report on Form 10-Q for the quarter ended
      April 3, 2005 of New River Pharmaceuticals
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)) 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 subsidiary, is made known to us by others within those
      entities, particularly during the period in which this report is being
      prepared;





(b)
    [Omitted
      in reliance on SEC Release No. 33-8238; 34-47986 Section
      III.E.]





(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: May
11, 2005




/s/  Randal
      J. KirkRandal
      J. KirkChairman,
      President and Chief Executive Officer(Principal
      executive officer)