The Strasbourg Agreement Concerning the International Patent Classification (or IPC), also known as the IPC Agreement, was signed in Strasbourg, France, on March 24, 1971 and entered into force on October 7, 1975. It establishes a common classification for patents for invention, inventors’ certificates, utility models and utility certificates, known as the “International Patent Classification” (IPC). The Agreement was amended on September 28, 1979.
States party to the Paris Convention for the Protection of Industrial Property (1883) may become party to the Strasbourg Agreement. As of May 2013, there are 62 contracting parties to the Strasbourg Agreement. The Holy See, the Iran and Liechtenstein signed the Agreement in 1971 but have not ratified it.