Objective: To assess the clinical outcome of women requiring laparoscopic excision of moderate-severe endometriosis in women with and without bowel resection and reanastomosis., Methods: Two hundred three patients with laparoscopically excised moderate (n = 67) or severe (n = 136) endometriosis (rAFS: revised endometriosis classification of the American Fertility Society) were prospectively followed during a median of 20 months (1-45 months) using a CONSORT-inspired checklist. Patients completed the EHP30 Quality-of-Life Questionnaire and visual analogue scales (VAS) for dysmenorrhea, chronic pelvic pain, and deep dyspareunia and answered questions about postoperative complications, reinterventions/recurrences, and fertility outcome 1 month before and 6, 12, 18, and 24 months after surgery. Clinical outcome was compared between women with deeply infiltrative endometriosis undergoing CO2 laser ablative surgery with bowel resection (study group, 76/203; 37%) and without bowel resection (control group, 127/203; 63%)., Results: Both groups were similar with respect to population characteristics and clinical outcome, except for mean rAFS score [higher in study group (73 ± 31) than in control group (48 ± 26)] and minor complication rate [higher in study group (11%) than in control group (1%)]. In both groups, mean VAS and EHP30 scores improved significantly and remained stable for 24 months after surgery, with a pregnancy rate of 51%. Within 1, 2, and 3 years follow-up, the cumulative reintervention rate was 1%, 7%, and 10%, respectively, and the cumulative endometriosis recurrence rate was 1%, 6%, and 8%, respectively., Conclusions: Clinical outcome after CO2 laser laparoscopic excision of moderate-severe endometriosis was comparable in women with or without bowel resection and reanastomosis, except for a higher minor complication rate occurring in women with bowel resection and reanastomosis (NCT00463398).