We describe a case of salt-losing congenital adrenal hyperplasia due to 21-hydroxylase deficiency complicated by a right adrenal adenoma. The development of adrenal adenoma or carcinoma in-patients with congenital adrenal hyperplasia (CAH) is rare; the etiology is not clear but is thought to be related to inadequate glucocorticoid therapy. Tumor formation is postulated to be a consequence of ACTH hypersecretion, which results from the lack of glucocorticoid synthesis. Our patient underwent clitorectomy and multiple constructive procedures as a newborn baby; she was managed with hormone replacement for many years. However while she took adequate mineralocortocoid dosage, she chronically tended to take inadequate doses of glucocorticoid seeking to increase her muscle ability. She developed a 6.5 cm adrenal tumor. She was managed by a hand-assisted laparoscopic radical adrenalectomy. The tumor was histologically consistent with adrenal adenoma. The importance of compliance with her medications was emphasized.