SECURITIES AND EXCHANGE COMMISSION
                           Washington, D.C. 20549-1004

                                    FORM 8-K
                    CURRENT REPORT PURSUANT TO SECTION 13 OF
                       THE SECURITIES EXCHANGE ACT OF 1934

          Date of Report (date of earliest event reported): May 6, 2004

                           Ciphergen Biosystems, Inc.
             (Exact name of Registrant as specified in its charter)

            Delaware                    000-31617              33-059-5156
(State or other jurisdiction of  [Commission File Number]    (I.R.S. Employer
 incorporation or organization)                           Identification Number)

                              6611 Dumbarton Circle
                                Fremont, CA 94555
                    (Address of principal executive offices)

                                 (510) 505-2100
              (Registrant's telephone number, including area code)


Item 7. Financial Statements and Exhibits

      (c) Exhibits.

            99.1  Press Release, dated May 6, 2004.

Item 12. Results of Operations and Financial Condition

      On May 6, 2004, Ciphergen Biosystems, Inc. issued a press release
announcing financial results for its fiscal first quarter ended March 31, 2004.
The press release is attached as Exhibit 99.1 to this Form 8-K.

      The information in this Current Report is being furnished and shall not be
deemed "filed" for purposes of Section 18 of the Securities and Exchange Act of
1934, as amended, or otherwise subject to the liabilities of that Section. The
information in this Current Report shall not be incorporated by reference into
any registration statement or other document pursuant to the Securities Act of
1933, as amended.


                                    SIGNATURE

      Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                       Ciphergen Biosystems, Inc.
                                       (Registrant)

Date: May 6, 2004                      By:  /s/ William Rich
                                       -----------------------------------------
                                       William E. Rich
                                       President and Chief Executive Officer


                                  EXHIBIT INDEX

Exhibit
Number                                 Description
-------        -----------------------------------------------------------------
 99.1          Press Release issued by Ciphergen Biosystems, Inc. on May 6, 2004