In January 2010, the Executive Board of the World Health Organization's (WHO) adopted a revision of the Guidelines for The WHO Review of Psychoactive Substances for International Control. These Guidelines govern the evaluation of substances for WHO's recommendations to the Commission on Narcotic Drugs (CND) as required by the Single Convention on Narcotic Drugs, 1961, and the Convention on Psychotropic Substances, 1971. This publication provides a comprehensive overview for all those who are involved in the evaluation process. It can be consulted by the Experts who serve on the Expert Committee on Drug Dependence, in order to make the right recommendation while following correct procedures, or by Representatives to the CND, in order to better understand any recommendations made to the Commission by WHO. Furthermore, it can help any interested person to understand the scheduling process in international drug control. This publication contains the text in its final form as it was adopted by the Executive Board, including three Appendices, of which Appendix 3 is a visual representation of the evaluation process in the format of a Flow Chart. Furthermore, this publication presents the Report by the Secretariat which contains the elucidation of the document by the WHO Secretariat to the Executive Board and the part of the Summary Records from the Executive Board session that reflects the discussion on the proposal, its amending and its adoption.