Exhibit 5.1

                OPINION OF JENKENS & GILCHRIST PARKER CHAPIN LLP


                                                      August 31, 2001

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,  for the  registration
for resale by the selling  stockholders  listed  therein of 1,895,364  shares of
Common Stock, par value $.01 per share (the "Common Stock"),  of the Company. Of
the  1,895,364  shares of Common Stock being  registered,  1,324,503  shares are
currently  issued and outstanding (the "Shares") and 570,861 shares are issuable
upon exercise of warrants by the selling stockholders (the "Warrants").

    In connection  with the  foregoing,  we have  examined  originals or copies,
satisfactory to us, of the Company's (i) Certificate of  Incorporation  and (ii)
Bylaws.  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 and the compliance  with  applicable
state  securities  laws, we are of the opinion that (i) the 1,324,503  shares of
Common  Stock  currently   outstanding  are  validly  issued,   fully  paid  and
nonassessable  and (ii) the  remaining  570,861  shares  of Common  Stock  being
registered,  if and when issued upon  surrender of the Warrants and exercise and
the payment of the exercise  price as provided in the Warrants,  will be validly
issued, fully paid and nonassessable.

    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" in the prospectus constituting part of the Registration Statement.

                                          Very truly yours,


                                    JENKENS & GILCHRIST PARKER CHAPIN LLP









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