Authentidate Holding Corp. (Nasdaq: ADAT) announced today that it will hold a conference call with investors on Thursday, June 2, 2005, at 4:30 p.m. ET to address general inquiries related to the announcement made by the Company on
May 27, 2005.

To participate on the call, investors should dial in to 800-811-7286, passcode 1427409. International callers should dial 913-981-4902, passcode 1427409.

The call will also be webcast via the Company's website at www.Authentidatehc.com. Once on the site, click on the "Investors" link, then on the "audio archives" link. There will then be a link for the call.

A replay of the call will also be available until 6 p.m. ET on June 9, 2005. The dial-in number for the replay is: 719-457-0820 passcode: 1427409. The call will also be archived on the Company's web site.

About Authentidate Holding Corp.

Authentidate Holding Corp. (AHC) is the holding company which operates its software and services businesses in three segments: the Security Software Solutions Segment (fka Authentidate Segment, including Authentidate, Inc., Trac Medical Solutions, Inc. and Authentidate International AG), the Document Management Solutions Segment (fka Docstar Division) and the Systems Integration Segment (fka DJS). The Company is a worldwide provider of secure enterprise workflow management solutions that incorporate its proprietary and patent pending content authentication technology. Authentidate's offerings include the United States Postal Service Electronic Postmark Service (USPS EPM(R)), electronic signing solutions, and electronic forms processing solutions. Authentidate also provides secure document management solutions, and enterprise network security products and services.

This press release contains forward-looking statements within the meaning of section 27A of the Securities Act of 1933 and section 21E of the Securities Act of 1934. When used in this release, the words "believe," "anticipate," "think," "intend," "plan," "will be," "expect," and similar expressions identify such forward-looking statements. Such statements regarding future events and/or the future financial performance of The Company are subject to certain risks and uncertainties, which could cause actual events or the actual future results of the Company to differ materially from any forward-looking statement. Such risks and uncertainties include, among other things, the availability of any needed financing, the Company's ability to implement its business plan for various applications of its technologies, the impact of competition, the management of growth, and the other risks and uncertainties that may be detailed from time to time in the Company's reports filed with the Securities and Exchange Commission. In light of the significant risks and uncertainties inherent in the forward-looking statements included herein, the inclusion of such statements should not be regarded as a representation by the Company or any other person that the objectives and plans of the Company will be achieved.

SOURCE: Authentidate Holding Corp.