The differential diagnosis of an incisional mass arising in a female includes endometriosis. The occurrence of abdominal scar endometriosis following hysterotomy is uncommon, being reported in less than 0.5% of patients undergoing cesarean section. Three cases of this unusual problem are reported, the experience at David Grant USAF Medical Center evaluated, and pertinent literature reviewed. The principles of surgical management include obtaining an accurate diagnosis and adequate excision.