The Patent Cooperation Treaty (PCT) is an international patent law treaty, concluded in 1970. It provides a unified procedure for filing patent applications to protect inventions in each of its Contracting States (see the Member Nations list below for current membership information).

A patent application filed under the PCT is called an international application or PCT application and it gives the inventors a priority of 31 months to deposit the patent in any of the member countries where they want to protect the invention.

The PCT Filing

A single filing of an international application is made with a Receiving Office (RO) in one language. It then results in a search performed by an International Searching Authority (ISA), accompanied with a written opinion regarding the patentability of the invention which is the subject of the application. It is optionally followed by a preliminary examination, performed by an International Preliminary Examining Authority (IPEA). Finally, the examination (if provided by national law) and grant procedures are handled by the relevant national or regional authorities.

For more information about the PCT, please consult the following official WIPO documents (external website):

• Protecting your Inventions Abroad: frequently asked questions about the Patent Cooperation Treaty (PCT) [PDF].
• The PCT Treaty.
• Regulations under the PCT (as in force from January 1, 2009).