When can an applicant file a Demand for international preliminary examination?

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.

An applicant can file a Demand for international preliminary examination after filing an international application under Chapter I of the PCT. According to MPEP 1864: “Once applicant has filed an international application under Chapter I of the PCT, applicant has the right to file a demand for preliminary examination under Chapter II of the Treaty.” It’s important to note that a proper Chapter I “Request” must be filed before a Demand can be submitted.