Interest in the problem of endemic goiter in Latin America has been greatly stimulated by the series of FAO-WHO conferences on the nutritional problems of Latin America, held successively in Montevideo in 1948 (1), Rio de Janeiro in 1950 (2), Caracas in 1953 (3), and Guatemala City in 1957 (4). Each of these recommended that surveys for the detection of endemic goiter be carried out in all of the countries of Latin America, and made it apparent that endemic goiter was a serious public health problem in the great majority of them. As a result, a large number of surveys have been published, and the information on the distribution of endemic goiter in the hemisphere has become increasingly complete. The report of the third Latin American nutrition conference (3) deserves special attention since a third of it was devoted to a complete analysis of the problem of endemic goiter in the Americas, including not only prevalence, contributory factors, and public health significance, but also practical details of prevention and treatment. The demonstration by Gongora and Mejia Caicedo (5) of the effectiveness of iodization of salt in the State of Caldas, Colombia, and the work of the Institute of Nutrition of Central America and Panama on the practical value of potassium iodate for the iodization of crude, moist salt (6, 7) have widespread significance. Attention should also be given to the metabolic investigations of Stanbury (8), carried out mainly in the Province of Mendoza in Argentina. More recently, epidemiological studies carried out in Brazil (9, 10) and Ecuador (unpublished data of the National Institute of Nutrition) have shed further light on environmental factors in the occurrence of endemic goiter. Extensive reviews of the occurrence of endemic goiter in Latin America were published in 1950 (11) and 1954 (12). A Bulletin of the World Health Organization, published in 1958 and devoted entirely to the problem of endemic goiter (13), contained a systematic survey by Kelly and Snedden of the world prevalence and geographic distribution of endemic goiter, including Latin America.