Androgen-producing tumors of the ovary are rare in postmenopausal women and are revealed by severe virilization. Leydig hilus cell tumors are the most frequent postmenopausal virilizing tumors. In this report, an unusual and rare cause of alopecia due to Leydig cell hyperplasia within the wall of a simple cyst and in the ovarian hilus is described.An 80 year-old woman complained of a 10-year history of severe androgenic alopecia associated with very mild facial hirsutism, without others signs of virilization. Hormonal blood levels showed markedly elevated testosterone. Computed tomographic scan of the adrenals and the ovaries revealed an enormous left ovarian cystic mass. Bilateral hystero-ophorectomy was performed. Histological examination demonstrated bilateral Leydig cell hyperplasia within the wall of the cyst and in the right ovarian hilus. Two months postoperative hormonal evaluation demonstrated dramatically decreased plasma levels of testosterone.The clinical, X ray and histologic aspects of this case, although rare, show that the presence of virilization should lead to a search for an androgen-secreting ovarian or adrenal tumor.