Steroid cell tumors are rare ovarian sex-cord stromal tumors with malignant potential. The majority of these tumors produce steroids with testosterone being the most common. The diagnosis of these rare tumors can be problematic especially in the case of a small nonpalpable ovarian tumor. A 41-year-old woman presented with the gradual onset of defeminization, mild hypothyroidism, and virilization. A physical examination revealed a relatively healthy woman with borderline hirsutism, clitoromegaly and adnexal fullness without a palpable tumor. Elevated serum levels of TSH and testosterone were found preoperatively. Five weeks after an oophorectomy, serum levels of TSH and testosterone returned to normal and menstruation returned. Nonpalpable virilizing ovarian steroid cell tumors may be difficult to diagnose. A careful study of the patient's history, the development of defeminization followed by virilization, and a "characteristic" ultrasonogram, can be helpful for diagnosis. Hormonal studies including thyroid function should also be considered in an ovarian steroid cell tumor.