The issue of increasing carbon dioxide in the atmosphere, its measurement and possible impact, is one of global dimensions. Several organizations with international membership are actively involved in efforts to resolve the unanswered questions surrounding this issue. This paper describes broadly these international organizations and the type of CO/sub 2/-related activities they conduct and outlines the CO/sub 2/ research work conducted through US biliateral arrangements. The major international organizations that engage in CO/sub 2/-related research are the World Meteorological Organization (WMO), the United Nations Environment Programme (UNEP), the International Council of Scientific Unions (ICSU), the Scientific Committee on Problems of the Environment (SCOPE), the European Community, the International Energy Agency (IEA), the International Institute for Applied Systems Analysis (IIASA), and the International Atomic Energy Agency (IAEA).