Nonclassic congenital adrenal hyperplasia, the mild form of the disease, is a common cause of hyperandrogenism in women. Although the same gene is involved in both the severe and mild forms, genetic mutations typically associated with the mild form of the disease only partially impair 21-hydroxylase activity. Thus, the patient with nonclassic congenital adrenal hyperplasia is in a fully compensated state; she does not have cortisol deficiency but rather manifestations of hyperandrogenism, usually later in childhood, around puberty, or in early adulthood (20–21). Nonclassic congenital adrenal hyperplasia is an important consideration in the differential diagnosis of female patients with symptoms or signs of hyperandrogenism, such as severe cystic acne, hirsutism, male pattern baldness, oligo-amenorrhea, or infertility. Nonclassic 21-hydroxylase deficiency, especially when it exists in conjunction with hyperinsulinemia, often results in the polycystic ovary syndrome, with its characteristic reproductive and metabolic comorbid conditions. Recognition of this disorder is crucial for family planning and management in women with hyperandrogenism. Men with nonclassic congenital adrenal hyperplasia are usually asymptomatic but may also present with early puberty or testicular adrenal rests.