Background: We present a 12-year-old girl with a 5-year history of progressive virilization. Results: Regarding elevated plasma levels of 17-hydroxyprogesterone (17-OHP) and androgens, normal ultrasound and CT scan of ovaries and adrenal glands, the nonclassic form of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency was presumed the cause of virilization. As the glucocorticoid therapy did not normalize high levels of 17-OHP and androgens, and the DNA analysis did not demonstrate a mutation causing CAH, a laparotomy was performed. Near the right ovary a tumor was found and extirpated. Pathohistological studies determined it to be a rare steroid cell tumor, ‘not otherwise specified’. Within the next months the signs of virilization resolved and menarche occurred. Conclusions: Steroid cell tumor should be considered in differential diagnosis of virilization in childhood. Regarding the age of our patient and pathohistological findings of the tumor, her prognosis is favorable.