Congenital adrenal hyperplasia (CAH) during pregnancy is a rare condition. Only a few cases have been reported in the literature. CAH patients has lower pregnancy rate compared to normal women. A 27-year-old nulliparous woman, a diagnosed case of 21-hydroxylase deficient simple virilising form of classic CAH visited. She got pregnant spontaneously without any trial of assisted reproductive technology. At the age of 12, she underwent clitoral resection and vaginoplasty. She took dexamethasone or prednisolone after operation. She delivered healthy singleton female baby by cesarean section. Four years later, she delivered healthy singleton female baby by repeat cesarean section. Two female babies have shown normal external genitalia. Here, we report a case of successful pregnancy and delivery in a patient with CAH.