How can an applicant file a delayed claim for foreign priority in a U.S. patent application?

If a claim for foreign priority is not presented within the required time period under 37 CFR 1.55, it is considered waived. However, the claim may be accepted if the priority claim was unintentionally delayed.

To file a petition for an unintentionally delayed priority claim, the applicant must submit:

1. The priority claim under 35 U.S.C. 119(a)-(d) or (f), 365(a) or (b), or 386(a) or 386(b) in an application data sheet, identifying the foreign application to which priority is claimed;
2. A certified copy of the foreign application, unless previously submitted or an exception applies;
3. The petition fee set in 37 CFR 1.17(m); and
4. A statement that the entire delay between the date the priority claim was due and the date it was filed was unintentional.

The Director may require additional information if there is a question whether the delay was unintentional. See 37 CFR 1.55(e).