How does a reissue affect the patent term?

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.

A reissue does not extend or alter the original patent term. According to MPEP 1460:

“The maximum term of the original patent is fixed at the time the patent is granted. While the term may be subsequently shortened, e.g., through filing of a terminal disclaimer, it cannot be extended through the filing of a reissue.”

This means that when a patent is reissued:

• The expiration date remains the same as the original patent
• No additional time is added to the patent term
• The term can be shortened (e.g., through a terminal disclaimer) but cannot be extended

Inventors and patent holders should be aware that seeking a reissue will not provide any extension to their patent protection period.