International Maritime Organization (IMO), specialized agency of the United Nations established in 1948, with headquarters in London and 168 member nations and three associate members. IMO is one of the smallest of the UN agencies. Originally called the Inter-Governmental Maritime Consultative Organization, it was renamed a decade after its formation. The IMO deals with various aspects of the regulation of international commercial shipping, encouraging cooperation among governments in a wide variety of technical matters. In addition, the agency supports high standards in maritime safety, promotes efficient navigation, and encourages the control and prevention of marine pollution. It has the power to enforce and administer matters relating to these aims. In the early 21st cent. the IMO has placed an increased emphasis on maritime security.