Universal Postal Union (UPU), specialized agency of the United Nations since 1948, with headquarters at Bern, Switzerland. Established in 1875 following adoption of the Universal Postal Convention, it is one of the oldest extant international governmental organizations. The union was associated with the United Nations in 1947. The Universal Postal Congress, the governing body, usually meets every four years to discuss and adopt a world postal strategy and consider the activities of the executive council, whose 40 members are elected on a geographical basis and meet yearly. Countries that belong to the union form a unified postal territory with easy international exchange of mail. The union also provides technical assistance and advice in attempts to improve postal service, especially in developing countries. It facilitates the development of the contemporary postal network which, in addition to the traditional delivery of mail, also includes electronic and financial services. The UPU has 191 member nations.

Universal Postal Union (UPU) Specialized agency of the United Nations (UN), established in 1947, that regulates international mail services. The Universal Postal Congress is the part of the UPU that determines postal rates and procedures. These are specified in an agreement called the Universal Postal Convention.