Exhibit 5




                                                     December 14, 1998

Xybernaut Corporation
12701 Fair Lakes Circle
Fairfax, Virginia 22033

Gentlemen:

         We  have  acted  as  counsel  to  Xybernaut  Corporation,   a  Delaware
corporation  (the "Company"),  in connection with the Registration  Statement on
Form S-3 (the  "Registration  Statement")  being filed with the  Securities  and
Exchange  Commission  under the Securities Act of 1933, as amended,  relating to
the offering of 630,701  shares (the  "Shares") of Common Stock,  par value $.01
per share (the "Common Stock") of the Company.

         Capitalized  terms used herein and not defined  shall have the meanings
given to them in the Registration Statement.

         In connection with the foregoing, we have examined originals or copies,
satisfactory  to us, of the Company's (i)  Certificate  of  Incorporation,  (ii)
By-laws and (iii) resolutions of the Company's board of directors.  We have also
reviewed  such  other  matters  of law and  examined  and  relied  upon all such
corporate  records,  agreements,  certificates  and other  documents  as we have
deemed relevant and necessary as a basis for the opinion hereinafter  expressed.
In such  examination,  we have assumed the  genuineness of all  signatures,  the
authenticity  of all documents  submitted to us as originals and the  conformity
with the  original  documents  of all  documents  submitted  to us as  copies or
facsimiles.  As to any facts  material to such  opinion,  we have, to the extent
that  relevant  facts  were  not  independently  established  by us,  relied  on
certificates  of  public   officials  and  certificates  of  officers  or  other
representatives of the Company.

         Based upon and subject to the foregoing, we are of the opinion that the
Shares,  when  issued  pursuant  to the terms  and  conditions  of the  Purchase
Agreement  and Form of Warrant filed as exhibits to the  Registration  Statement
will be validly issued, fully paid and non-assessable.

         We hereby  consent to the  filing of this  opinion as an exhibit to the
Registration Statement.

                                        Very truly yours,


                                         /s/ Parker Chapin Flattau & Klimpl, LLP
                                             PARKER CHAPIN FLATTAU & KLIMPL, LLP