Forty-two patients who underwent a second-look laparoscopy after a unilateral or bilateral intraperitoneal cystectomy for treatment of an ovarian endometrioma of greater than 3 cm were included. At second-look laparoscopy, 92.4% of the adnexae treated for a large endometrioma had no deep ovarian endometriosis. Adhesion de novo formation occurred in 21% of the treated adnexae and in 17% of the contralateral adnexae. Complete or partial recurrence of dense adhesions occurred in 82% of the cases. Laparoscopic cystectomy is effective in treating large endometriomas. However, operative difficulties may be encountered, explaining persistent endometriomas and postoperative adhesions.