What is an interfering claim in a patent application?

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.

An interfering claim in a patent application refers to a claim that covers the same subject matter as a claim in another application or patent by a different inventor. According to MPEP 2304.04(a), “If the applicant already has a claim to the same subject matter as a claim in the application or patent of another inventor, then there is no need to require the applicant to add a claim to have a basis for an interference.”