Can I perfect a claim for foreign priority after my patent has been issued?

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, you can perfect a claim for foreign priority after your patent has been issued. There are two main methods:

1. Certificate of Correction: This is generally the preferred method if the requirements of 37 CFR 1.55 are met and no further examination is required. As stated in the MPEP, Except in certain situations, a certificate of correction can generally be used to perfect a claim to foreign priority where a petition under 37 CFR 1.55(e) to accept an unintentionally delayed priority claim is filed with a request for a certificate of correction in an issued patent.
2. Reissue Application: This method is necessary in situations where further examination would be required or when the requirements of 35 U.S.C. 119(a)-(d) or (f) were not satisfied in the patented application or its parent prior to issuance.