Over the last 80 years, a worldwide system for the control of drugs of abuse has developed gradually through the adoption of a series of international treaties. The key multilateral conventions currently in force are the Single Convention on Narcotic Drugs of 1961, as amended by the 1972 Protocol; the Convention on Psychotropic Substances of 1971; and the 1988 United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances. The aim of these international instruments has been to limit the production, processing, trade, and use of drugs to medical and scientific purposes only. The Global Program of Action adopted in 1990 by the U.N. General Assembly facilitates international cooperation against the illicit production, supply, demand, trafficking, and distribution of narcotic drugs and psychotropic substances. International bodies that are responsible for developing and coordinating the implementation of international drug policy are the Commission on Narcotic Drugs and the International Narcotics Control Board. A discussion of the implementation of treaty provisions by national governments focuses on the importance of national legislation, interministerial coordination, law enforcement mechanisms, and health and social mechanisms. The paper concludes with a description of the mandate and functions of the UNDCP, which is looked to by the international community to provide leadership for international drug control efforts and to act as the main vehicle for ensuring the coherence of United Nations drug control activities in all sectors. Appended listing of useful Web sites