Patients with female pseudohermaphroditism have female internal genitalia and karyotype (XX) and various degree of external genitalia virilization. External genitalia is musculinized congenitally when female fetus is exposed to excess androgenic environment. Congenital adrenal hyperplasia (CAH), mostly 21-hydroxylase deficiency, is the most common cause. Maternal androgen excess due to maternal ovarian tumor or drug intake also causes female pseudohermaphroditism. Combination of hormonal therapy and surgical correction is required for CAH. When appropriate treatments were given, normal puberty, fertility and child bearing are possible. HLA typing in patient's family is useful for identifying heterozygote and homozygote, because of close linkage of 21-hydroxylase gene and HLA gene. Prenatal diagnosis and genetic diagnosis for female pseudohermaphroditism due to 21-hydroxylase deficiency can be performed, however prenatal treatment is not completely established.