How do I claim foreign priority in a U.S. patent application?

To claim foreign priority in a U.S. patent application, you must:

1. File the U.S. application within 12 months (6 months for design applications) of the foreign filing date.
2. Submit a claim for priority identifying the foreign application.
3. File a certified copy of the foreign application.

For applications filed on or after September 16, 2012, 37 CFR 1.55(d)(1) requires that the claim for priority be presented in an application data sheet. The claim must identify the foreign application by specifying the application number, country (or intellectual property authority), day, month, and year of its filing.

A certified copy of the foreign application must also be filed within a specified time period, usually within the later of 4 months from the actual U.S. filing date or 16 months from the foreign filing date.