The basal cell nevus syndrome is a hereditary affection characterized primarily by multiple genetically determined basal cell carcinomas, cysts of the jaws, peculiar pits of the hands and feet, and developmental anomalies of the ribs, spine, and skull. These, as well as other associated anomalies, serve to differentiate the nevoid basal cell carcinoma from tumors which may have overlapping clinical and histopathological features, including ordinary basal cell cancers. These tumors are not epithelioma adenoides cysticum. Problems of management were occasionally profound. In seven families with 43 affected members, the syndrome was found with equal frequency in males and females and is conditioned by a highly penetrant autosomal dominant gene. No abnormality in chromosome number or structure was observed.