Endometriosis is a hormone-dependent inflammatory disease that is usually characterized by infertility and pain symptoms. This disease mainly occurs during the reproductive years and is rarely diagnosed after menopause. We discuss the physiopathology of this condition after menopause as well as treatment options and the risk of malignant transformation. Occurrence or progression of postmenopausal endometriosis lesions could be related to extra-ovarian production of estrogen by endometriosis lesions and adipose tissue, which becomes the major estrogen-producing tissue after menopause. Postmenopausal women with symptomatic endometriosis should be managed surgically because of the risk of malignancy; medical treatments can be used in cases of pain recurrence after surgery. Aromatase inhibitors act by decreasing extra-ovarian estrogen production and by blocking the feed-forward stimulation loop between inflammation and aromatase within endometriosis lesions. The evidence is currently insufficient to support a conclusion about the optimal hormone replacement therapy for women with endometriosis. The question of malignant transformation of endometriosis in response to hormone replacement therapy in women with a history of endometriosis remains unanswered and needs a long-term follow-up study to evaluate the risk of an adverse outcome. Further studies should be performed to determine the optimal management of menopausal women with endometriosis.