The radiological health program of the Pan American Health Organization (PAHO) was established in 1960. Although the program has undergone various organizational changes, it has been in continuous operation to the present, extending through the administrations of five of the Directors of the Pan American Sanitary Bureau (PASB, PAHO’s Secretariat) in various PAHO divisions or areas of work. Its program emphasis has evolved according to the requirements of the PAHO Member States. However, the program has essentially remained a unit with activities revolving around research, training, radiation protection, and services in the areas of public health and clinical medicine.