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.
The validity period of a foreign filing license depends on the type of license issued. According to MPEP 140:
“A foreign filing license is not required to file a patent application in another country if the invention was not made in the United States. A license is required if the invention was made in this country and:
- An application on the invention has been filed in the United States less than six months prior to the date on which the application is to be filed abroad, or
- No application on the invention has been filed in the United States.”
In essence, a foreign filing license granted as part of the regular patent application process remains valid for six months from the filing date. After six months, no additional license is required. However, if you obtain a petition-based license (e.g., for inventions not yet filed in the U.S.), the license will specify its scope and duration in the grant letter.
For more information on foreign filing license, visit: foreign filing license.