This rare syndrome occurs in older children and in adults. It is manifested by virilism in females and by excessive masculinization in males. It may be due to idiopathic adrenal cortex hyperplasia, adrenal cortex adenoma, or cortex carcinoma. Tumor is more common than hyperplasia in these patients. Virilism in a female child or adult leads to hirsutism, clitoral enlargement, deepening of the voice, masculine contour, and breast atrophy. The syndrome may be simulated in females by idiopathic hirsutism, arrhenoblastoma of the ovary, and possibly by the Stein-Leventhal syndrome. Urinary 17-KS values are elevated with normal or decreased 17-OHCS values when the adrenal is involved. Ovarian arrhenoblastoma gives normal or only slightly elevated urine 17-KS values, since androgen is produced in smaller quantities but is more potent, thus giving clinical symptoms without greatly increased quantities. In prepubertal boys, the symptoms of virilism are those of precocious puberty; in men, excessive masculinization is difficult to recognize. A similar picture may be associated with certain testicular tumors.