What is the critical reference date for international applications?

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.

For international applications, the critical reference date depends on whether the international application was filed before or on/after November 29, 2000. MPEP 2136.03 provides specific guidance:

“If the international application has an international filing date prior to November 29, 2000, the international application was not published under 35 U.S.C. 122(b) by WIPO. Any U.S. patent or U.S. patent application publication which claims the benefit of an international filing date prior to November 29, 2000 is subject to pre-AIPA 35 U.S.C. 102(e) as in effect on November 28, 2000.”

For international applications filed on or after November 29, 2000:

• The critical reference date is the international filing date only if the international application designated the United States and was published by the World Intellectual Property Organization (WIPO) under PCT Article 21(2) in English.
• If these conditions are not met, the critical reference date is the earlier of the date of compliance with 35 U.S.C. 371(c)(1), (2), and (4), or the filing date of the later-filed U.S. application that claimed the benefit of the international application.