Congenital adrenal hyperplasia (CAH) is an inherited disorder of adrenal steroidogenesis often diagnosed in infancy. Gynecologists may encounter adult patients with CAH due to the clinical effects of increased androgens, e.g. hirsutism, clitoromegaly, oligomenorrhea, or, rarely, pelvic masses. This case report reviews the association of para-ovarian adrenal rest tumors with CAH, and the role of gynecologists in their evaluation and treatment. A 23-year-old woman with CAH (21-hydroxyase deficiency) untreated for the past 5 years presented with a pelvic mass and elevated serum testosterone (1433 ng/dL) and plasma ACTH (1117 pg/mL). Intraoperative findings revealed multiple retroperitoneal masses. Final pathology demonstrated adrenal rest tissue. Para-ovarian and ovarian adrenal rest tumors may present as a rare gynecologic manifestation in patients with untreated CAH.