Can a reissue application be filed to add narrower claims?

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.

Yes, a reissue application can be filed solely to add narrower claims to a patent. The MPEP cites the case of In re Tanaka, which states: the omission of a narrower claim from a patent can render a patent partly inoperative by failing to protect the disclosed invention to the full extent allowed by law.

This means that a reissue applicant can:

• Retain the broad independent claims of the original patent
• Add new dependent claims that are narrower in scope

It’s important to note that this does not require narrowing of the existing patent claims.