Can third parties participate in ex parte reexamination proceedings?

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.

Third party participation in ex parte reexamination proceedings is limited. According to the MPEP, “The active participation of the ex parte reexamination requester ends with the reply pursuant to § 1.535, and no further submissions on behalf of the reexamination requester will be acknowledged or considered.“

After the reexamination is ordered, third party submissions are generally not allowed unless they meet specific criteria. The MPEP states: “Submissions by third parties, filed after the date of the order for ex parte reexamination pursuant to § 1.525, must meet the requirements of and will be treated in accordance with § 1.501(a).” This ensures that the proceedings remain ex parte as intended by the legislation.