How are foreign patent documents classified in the USPTO’s patent database?

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.

Foreign patent documents in the USPTO’s patent database are classified according to the U.S. Patent Classification System. The MPEP states:

“Foreign patent documents that have not been abstracted into the U.S. Patent Classification System are available for searching on an as-disclosed basis.“

This means that while some foreign patents are fully integrated into the U.S. system, others may require separate searching based on their original disclosure.