What are the key differences between ex parte reexamination ordered under 35 U.S.C. 257 and 35 U.S.C. 302?

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.

There are several key differences between ex parte reexamination ordered under 35 U.S.C. 257 (as a result of supplemental examination) and 35 U.S.C. 302:

• Patent owner’s statement rights
• Timing of patent amendments
• Basis for reexamination
• Scope of issues considered
• Definition of material information

According to MPEP 2823: “Ex parte reexamination ordered under 35 U.S.C. 257, i.e., as a result of a supplemental examination, will be conducted in accordance with regulations and procedures that govern ex parte reexamination ordered pursuant to 35 U.S.C. 302 (e.g., 37 CFR 1.530 through 37 CFR 1.570), except that” the above-mentioned differences apply.