Exhibit 31.1

                                 CERTIFICATION

I, Surendra Pai,certify that:

1. I have reviewed this Amended Quarterly Report on Form 10-Q/A of Authentidate
Holding Corp.;

2. Based on my knowledge, this report does not contain any untrue statement of a
material fact or omit to state a material fact necessary to make the statements
made, in light of the circumstances under which such statements were made, not
misleading with respect to the period covered by this report;

3. Intentionally omitted.

4. Intentionally omitted.

5. Intentionally omitted.

Date: December 27, 2005                          Name: /s/Surendra Pai
                                                       --------------------
                                                 Title: Chief Executive Officer