EXHIBIT 31.1

                                 CERTIFICATIONS

I, Michael A. McManus, Jr., certify that:

I have reviewed this annual report on Form 10-K of MISONIX, INC.;

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;

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;

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))  [*** Omitted  pursuant to extended
compliance period] 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)   [*** Omitted pursuant to extended compliance period];

      (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

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:  September 15, 2004

                                           /s/ Michael A. McManus, Jr.
                                           -------------------------------------
                                           Michael A. McManus, Jr.
                                           President and Chief Executive Officer