The World Organisation for Animal Health (OIE) is an inter-governmental organisation whose 181 Members have mandated it to improve animal health and welfare worldwide. Created in 1924 under the name of Office International des Epizooties, it had only 28 member countries at the beginning. Those countries were: Argentine Republic, Belgium, Brazil, Bulgaria, Denmark, Egypt, Spain, Finland, France, Great Britain, Greece, Guatemala, Hungary, Italy, Luxemburg, Morocco, Mexico, the Principality of Monaco, the Netherlands, Peru, Poland, Portugal, Romania, Siam (Thailand), Sweden, Switzerland, the Czechoslovak Republic, and Tunisia.
Original members are listed bold. The dates are those from the adhesion to the UN.