What is a certified copy of a foreign application and when must it be filed?

A certified copy of a foreign application is an official copy of the foreign patent application, certified by the patent office where it was filed. It is required to perfect a claim of foreign priority in a U.S. patent application.

According to 37 CFR 1.55(f), for applications filed on or after March 16, 2013:

“A certified copy of the foreign application must be filed within the later of four months from the actual filing date of the application, or sixteen months from the filing date of the prior foreign application, in an original application under 35 U.S.C. 111(a) filed on or after March 16, 2013, except as provided in paragraphs (h), (i), and (j) of this section.”

There are exceptions to this requirement, such as when the foreign application was filed in a foreign intellectual property office participating in a priority document exchange agreement with the USPTO. In such cases, the applicant can request that the USPTO retrieve the certified copy electronically.