The authors report three cases of endometriosis of the rectus abdominis muscle, presenting as a mass of the abdominal wall associated with pain during menstruation in women with a history of cesarean section. Treatment consisted in wide surgical resection followed by prosthetic abdominal wall repair in one recurrent case. Abdominal wall endometriosis is a rare disease that can be explained by grafting of endometrial cells to the abdominal wall during laparotomy for pelvic surgery, particularly cesarean section. Isolation of the abdominal wall during cesarean section and irrigation of the abdominal wall at the end of the operation are two theoretical measures designed to prevent endometrial cell engraftment. When abdominal wall endometriosis occurs, only radical surgical resection can prevent recurrence.