Exhibit 5.1
 
                                                                 August 25, 1998
 
Dectron Internationale Inc.
4300 Poirier Blvd.
Montreal, Quebec H4R 2C5
Canada
 
Gentlemen:
 
    We have acted as counsel to Dectron Internationale Inc. (The "Company") in
connection with its filing of the registration statement on Form SB-2
(Registration No. 333, the "registration Statement") covering (i) 1,150,000
shares of common stock, no par value (the "Common Stock"), including 150,000
shares subject to an over-allotment option, (ii) 1,437,500 redeemable warrants
(the "Redeemable Warrants"), including 150,000 Redeemable Warrants subject to an
over-allotment option, with each Redeemable warrant entitling the holder to
purchase on share of Common Stock, and (iii) warrants to be issued to the
underwriter (the "Underwriters' Warrants") to purchase up to 150,000 additional
shares and/or 150,000 additional Redeemable Warrants, all as more particularly
described in the Registration Statement.
 
    In our capacity as counsel to the Company, we have examined the Company's
Certificate of Incorporation and By-laws, as amended to date, and the minutes
and other corporate proceedings of the Company.
 
    With respect to factual matters, we have relied upon statements and
certificates of officers of the Company. We have also reviewed such other
matters of law and examined and relied upon such other documents, records and
certificates as we have deemed relevant hereto. In all such examinations we have
assumed conformity with the original documents of all documents submitted to us
as conformed or photostatic copies, the authenticity of all documents submitted
to us as originals and the genuineness of all signature on all documents
submitted to us.
 
    On basis the forgoing, we are of the opinion that:
 
        the shares of Common Stock covered by the Registration Statement and the
    Common Stock issuable upon exercise of the Underwriters' Warrants have been
    validly authorized and will, when sold as contemplated by the Registration
    Statement, be legally issued, fully paid and non-assessable;
 
        the Redeemable Warrants covered by the Registration Statement and the
    Redeemable Warrants issuable upon exercise of the Underwriters' Warrants
    (connectively and the "Registered Warrants") will, when soled as
    contemplated by the Registration Statement, be legally issued and will
    constitute legal, valid and binding obligations of the Company; and
 
        the shares of Common Stock issuable upon exercise of the Redeemable
    warrants will, upon issuance and payments in accordance with the terms of
    the Registered Warrants, be legally issued, fully paid and non-assessable;
 
        We hereby consent to the filing of this opinion as an exhibit to the
    Registration Statement and to the reference made to us under the caption
    "Legal Matters" int he prospectus constituting part of the Registration
    Statement.
 

                               
                                Very truly yours,
 
                                By:                   /s/ GSKF
                                     -----------------------------------------
                                            GERSTEN, SAVAGE, KAPLOWITZ &
                                                  FREDERICKS, LLP