The procedure for patent applications filed to the patent office of a given country by non-residents under Patent Co-operation Treaty (PCT).

Patent Co-operation Treaty (PCT) is a treaty signed on June 19, 1970 in Washington (entered into force on June 1, 1978) which introduced international patent applications entailing the same effects as applications filed under national procedure in every country of the treaty signatories. International patent applications are sent to the World Intellectual Property Organization (WIPO) and then examined by the European Patent Office (playing the role of the International Searching Authority, ISA). The intermediary in filing patent applications of residents according to PCT procedure in Poland is Polish Patent Office. A PCT application means that the applicant applies for the protection of an invention in many different countries (at least three and maximum in all countries-signatories which are currently 142). Patents for inventions filed under PCT procedure are still granted by individual national patent offices. Poland joined Patent Co-operation Treaty in December 1990.