Patent Cooperation Treaty (PCT) is a multilateral treaty. This became effective in 1978 and it is established to eliminate some of the duplication involved when obtaining patent protection for the same invention in several countries. Patent Cooperation Treaty has more than 40 nations as signatories. The Patent Cooperation Treaty makes it possible to file and prosecute a single international application, which has the same effect as filing a separate application in each Patent Cooperation Treaty nation that the inventor designates at the time of filing the application. The Patent Cooperation Treaty neither creates an international patent nor changes the substantive requirements of patentability in any individual Patent Cooperation Treaty nation (including the US).

It is important to conduct patent analysis or search before filing an application for a patent. This is so because patent analysis can help determine if the invention is novel or new which is the primary consideration for a patent to be granted.

A patent analysis will identify existing inventions that may block your patent application. The results on a patent analysis can also be used in writing your patent application. A basic patent analysis includes browsing through patents and published patent applications listing in the United States. A more extensive patent analysis includes patents and patent applications in Europe and Japan, as well as published patent applications through the Patent Cooperation Treaty (PCT). Patent professionals, such as registered patent agents and patent attorneys, have access to databases worldwide for patent analysis and patent applications.