Filing Pursuant to Rule 424(b)(2)
                                            Registration Statement No. 333-33968


                              PROSPECTUS SUPPLEMENT
                      (TO PROSPECTUS DATED APRIL 12, 2000)

                                  COMMON STOCK

                                APA OPTICS, INC.


         You should read this prospectus supplement and the accompanying
prospectus carefully before you invest. Both documents contain information you
should consider when making your investment decision.

         See "Risk Factors" beginning on page 6 of the prospectus to read about
factors you should consider before buying shares of the common stock.

         This supplement changes the information contained in the prospectus to
reflect:

         o        Our redemption of all outstanding preferred stock.

         o        A reduction in the exercise price of warrants held by Strong
                  River, Bay Harbor, Ampal, and Wharton Capital Partners, Ltd.
                  to $14.72 per share (reduced from $49.47 in the case of
                  Wharton and from $35 in the case of the other holders) by
                  operation of the anti-dilution provision of the warrants, and
                  a commensurate increase in the aggregate number of shares of
                  common stock purchasable from 57,500 to 144,091 shares.

         o        Changes in ownership of our common stock by the selling
                  shareholders as a result of purchase of shares from APA in a
                  registered public offering or in the market, the redemption of
                  the preferred stock, and the change in the warrants, described
                  above.

         The following amended table sets forth the name of each person who is
offering shares of common stock by this prospectus, the number of shares of
common stock owned by each person as of July 27, 2000, the number of shares of
common stock that may be sold in this offering, and the number of shares of
common stock each person will own after the offering, assuming they sell all of
the shares offered.


<TABLE>
<CAPTION>

- -------------------------------------- ----------------------------------------------- -----------------------
                                           Beneficial Ownership Prior to Offering        Shares to be Sold
Name                                             Shares                Percentage           In Offering
- -------------------------------------- --------------------------- ------------------- -----------------------

<S>                                             <C>                     <C>                    <C>
Strong River Investments                         119,525 (1)               *                   71,331

Bay Harbor Investments, Inc.                      23,777 (2)               *                   23,777

Ampal American-Israel Corporation                 23,777 (3)               *                   23,777

Wharton Capital Partners, Inc.                    25,206 (4)               *                   25,206

</TABLE>




- -------------------------------
*        Less than 1%.
(1)      Consists of 71,331 shares of our common stock issuable to Strong River,
         upon exercise of its warrants and 48,194 shares of common stock held by
         Strong River which are not offered by this prospectus.
(2)      Consists of the 23,777 shares of common stock issuable to Bay Harbor
         upon exercise of its warrants.
(3)      Consists of 23,777 shares of our common stock issuable to Ampal upon
         exercise of its warrants.
(4)      Consists of the shares of our common stock issuable to Wharton Capital
         Partners, Inc. upon exercise of the warrant it received for placing the
         preferred stock.


MARKET FOR OUR COMMON STOCK

         On August 1, 2000, the last reported sales price of our common shares
on the Nasdaq SmallCap Market was $14.75 per share. Our common stock is listed
on the Nasdaq SmallCap Market under the symbol "APAT." As of August 1, 2000,
11,893,860 shares of our common stock were issued and outstanding.

GENERAL

         You should rely only on the information provided or incorporated by
reference in this prospectus supplement and the prospectus. We have not
authorized anyone else to provide you with different information. You should not
assume that the information in this prospectus supplement is accurate as of any
date other than the date on the front of these documents.

               ---------------------------------------------------

         The Securities and Exchange Commission and state securities regulators
have not approved or disapproved these securities, or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

               ---------------------------------------------------

            The date of this prospectus supplement is August 2, 2000