How does the duty of disclosure differ between ex parte reexamination under 35 U.S.C. 302 and 35 U.S.C. 257?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The duty of disclosure differs between ex parte reexamination proceedings under 35 U.S.C. 302 and 35 U.S.C. 257. MPEP 2280 explains:

“The material to patentability standard set forth in 37 CFR 1.56(b), which is applicable to patent applications, and not the standard set forth in 37 CFR 1.555(b), applies in ex parte reexamination proceedings ordered under 35 U.S.C. 257 (as a result of a supplemental reexamination proceeding).”

Key differences:

• 35 U.S.C. 302 proceedings: Limited to patents and printed publications
• 35 U.S.C. 257 proceedings: Not limited to patents and printed publications, similar to patent application examination

This distinction affects what information must be disclosed in each type of proceeding.