What are the consequences of failing to show diligence in filing a reissue 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.

Failing to show diligence in filing a reissue application can have serious consequences, potentially resulting in the rejection of the reissue application. The MPEP 1403 states:

“If it is determined that there was a failure to exercise due diligence in filing the reissue application, the application should be rejected as a recapture of the subject matter that was surrendered in order to obtain the original patent.”

This means that:

• The reissue application may be rejected
• The applicant may lose the opportunity to correct errors in the original patent
• Subject matter surrendered during the original prosecution cannot be recaptured
• The original patent may remain invalid or defective

To avoid these consequences, applicants should maintain thorough documentation of their efforts towards filing the reissue application and be prepared to demonstrate diligence if questioned by the USPTO.