Why did the USPTO set a time limit for requesting ex parte reexamination?

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 USPTO set a time limit for requesting ex parte reexamination to align with the period of enforceability of a patent. As explained in MPEP 2211, “the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents which cannot be enforced.” This rationale was supported in the case of Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985). The time limit ensures that USPTO resources are focused on patents that can still be enforced.