Ovarian stromal hyperthecosis is an uncommon non-neoplastic ovarian disorder resulting in excessive androgen production and virilization. We report two cases of ovarian stromal hyperthecosis in postmenopausal women. Both complained of symptoms of virilization, with high serum testosterone levels. Pelvic imaging showed homogenous ovaries of normal or increased size. Ovarian venous sampling was performed in one patient and found a left-to-right androgen concentration gradient. Both women underwent first-line bilateral oophorectomy. Pathology found bilateral ovarian stromal hyperthecosis. Postoperatively, clinical and biological hyperandrogenism resolved within few months. Hyperthecosis is a benign virilizing condition almost always involving both ovaries. Numerous virilizing diseases, and especially androgen-producing neoplasms, have to be ruled out before considering this diagnosis.