Abstract
Carcinoma of the kidney was induced in the FAC-F1 strain and the Sprague-Dawley rat by x-ray irradiation. The incidence of carcinoma averaged 36.5 per cent. These tumors were characterized as bilateral, multicentric, miliary and cortical in type. Arteriosclerotic and nephrosclerotic changes were always present in association with these induced x-ray carcinomas.