The International Narcotics Control Board was invited by the Commission on Narcotic Drugs in March 2010 to include in its Report for 2010 information on the availability of internationally controlled substances for medical requirements. In recognition of its importance, the Board decided to devote a supplement to its annual Report to this subject. This format allows the Board to provide adequate information on the present situation, globally and regionally, to highlight major impediments and to formulate recommendations to improve the availability of internationally controlled substances for medical and scientific purposes. A detailed analysis is contained in the Board's technical publications on narcotic drugs and psychotropic substances.