The Symposium on Radionuclides in the Food Chain, sponsored by the Interna tional Life Sciences Institute in association with the International Institute for Applied Systems Analysis, was intended to bring together policymakers and other representatives of the food industry with radiation experts involved in measuring and assessing radioactivity in foodstuffs. The symposium was made timely by the problems arising from the nuclear reactor accident at Chernobyl, in the USSR, which brought out the lack of international agreement on guidance for responding to such radionuclide contamination of food and foodstuffs. The presentations by the radiation experts covered the sources of radionu clides-natural radioactivity, fallout from nuclear weapons tests, routine releases from nuclear facilities, and various nuclear accidents. The speakers represented a broad distribution in both scientific disciplines and international geographic origin. They summarized the available data on measurements and indicated the current procedures for assessing radiation exposure. It was hoped that the food industry representatives would bring out the problems posed to industry and governments by the presence of radioactivity in food.