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                                                                     EXHIBIT 5.1

                [LETTERHEAD OF FREEDMAN, LEVY, KROLL & SIMONDS]


                                                              CABLE "ATTORNEYS"
                                                       TELECOPIER: 202-457-5151


                                January 8, 1998

Infodata Systems Inc.
12151 Monument Drive
Fairfax, Virginia 22033

Gentlemen:

          Re:  Infodata Systems Inc.
               Registration Statement on Form SB-2

     We have been engaged as special counsel to Infodata Systems Inc. (the
"Company") for the purpose of rendering an opinion as to the legality of the
issuance of shares of the Company's Common Stock. In connection with the
Registration Statement on Form SB-2 (Registration No. 333-42611) filed by the
Company with the Commission (together with all exhibits thereto, the
"Registration Statement"). The Registration Statement relates to an
underwritten public offering by the Company of up to 1,000,000 shares of the
Company's common stock, par value of $.03 per share, (the "Shares") to be made
through a group of underwriters represented by Southeast Research Partners,
Inc. and GKN Securities Corp. Such amount includes 150,000 Shares underlying an
over-allotment option granted to the underwriters. A form of underwriting
agreement has been filed as Exhibit 1 to the Registration Statement (the
"Underwriting Agreement").

     This opinion is being delivered to the Commission as Exhibit 5 to the
Registration Statement.

     We have examined (1) the Articles of Incorporation, and all amendments
thereto, certified by the Secretary of State of the Commonwealth of Virginia,
(2) the By-Laws of the Company, certified by the Secretary of the Company as
being those currently in effect, (3) the Registration Statement, and (4) such
other corporate records, certificates, documents and other instruments as in
our opinion are necessary or appropriate in connection with expressing the
opinions set forth below.
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     Based upon the foregoing, it is our opinion that:

     1.   The Company is a corporation duly organized and validly existing
          under the laws of the State of Virginia.

     2.   When the following events shall have occurred:

          (a)  the Registration Statement, as amended, shall have been ordered
               effective by the Commission in accordance with the Securities
               Act of 1933, as amended, and

          (b)  the Shares shall have been paid for and issued in accordance
               with the terms of the Underwriting Agreement and as provided in
               the Registration Statement,

the Shares thus sold will be legally issued, fully paid and non-assessable.

     This firm hereby consents to the reference to it under the heading "Legal
Matters" appearing in the Prospectus which is part of the Registration
Statement.

                                        Sincerely,
          
                                        /s/ Freedman, Levy, Kroll & Simonds

                                        Freedman, Levy, Kroll & Simonds
    

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