Endometriosis occurs in 5% to 10% of women of childbearing age and involves the proliferation of endometrial tissue outside the uterine cavity. Thoracic endometriosis is the most frequent extrapelvic manifestation of endometriosis, numbering some 100 reported cases. It may include spontaneous pneumothorax, hemoptysis, chest pain, bronchiectasis, pneumomediastinum, or mediastinal bleeding. Because the tissue is hormonally responsive, all of these manifestations are related to the menstrual cycle (catamenial) and are likeliest to occur during menses. We report the successful anesthetic management of a patient with thoracic endometriosis and recurring catamenial pneumothorax who presented for elective pelvic surgery.