Virilization of the female may occur from adrenal cortex hyperplasia during fetal life or at any period after birth. The syndrome has been recognized in varying degrees of severity, ranging from advanced masculinization of the host to such mild manifestations as oligomenorrhea, infertility, and mild hirsutism.* This paper is limited to a discussion of adrenal cortex hyperplasia as a cause of virilization in the female. In a previous publication we reviewed this and other causes of virilization of the female child and adult. 4 The study of the urinary corticoid excretions has aided the understanding of the syndromes associated with adrenal cortex hyperplasia.† More recently the histochemical demonstration of zonal pathology in the adrenal cortex of patients with adrenal hyperplasia has improved our understanding of etiology and treatment of this disease.‡ Some types of adrenal hyperplasia may be treated surgically, but adrenal virilism from hyperplasia is fundamentally an endocrine disorder