Leydig cell tumors are rare ovarian steroid cell neoplasms. More than 75% of patients show signs of virilization due to overproduction of testosterone. We report a case of an 8-year-old woman with progressive signs of virilization, and presenting vaginal bleeding. Clinical analyses revealed high levels of serum testosterone, delta 4-androstenedione and estradiol, and also inappropriate low levels of gonadotrophins for a post-menopausal woman. Transvaginal ultrasound showed no evidence of ovarian tumor, but pelvic and abdominal computerized axial tomography imaging revealed a left ovarian solid nodule, and no evidence of alteration in the adrenal glands. Total hysterectomy and bilateral salpingoophorectomy were performed. Histopathology and immunohistochemistry confirmed the diagnosis of Leydig cell tumor. After surgery, androgen levels returned to normal, and there was regression of the signs of virilization.