BACKGROUND: Surgical excision of parametrial endometriosis carries a risk of postoperative bladder, bowel, or sexual dysfunction due to pelvic autonomic nerve injury. Nerve-sparing surgery reduces these adverse effects and improves quality of life. However, experience remains limited, and further studies are needed to evaluate its feasibility and functional outcomes. METHODS: This retrospective case series included 29 patients with advanced parametrial endometriosis who underwent nerve-sparing surgery. The primary objective was to evaluate postoperative urinary and defecatory function; the secondary objective was to assess surgical complications. RESULTS: Among 29 patients, 7 (24.1%) had stage III disease and 22 (75.9%) had stage IV disease per American Association of Gynecologic Laparoscopists (AAGL) criteria. Surgical approaches included laparoscopy in 17 (58.6%), robotic surgery in 10 (34.5%), and conversion to laparotomy in 2 (6.9%). All cases involved nerve-sparing radical excision of endometriosis. Additional procedures included ureterolysis in all 29 patients (100%), enterolysis in 19 (65.5%), bowel shaving in 9 (31.0%), discoid resection in 5 (17.2%), segmental resection in 3 (10.3%), diaphragm excision in 2 (6.9%), partial cystectomy in 2 (6.9%), appendectomy in 3 (10.3%), and abdominal wall excision in 1 (3.4%). Operative time was 284 ± 99.3 min; estimated blood loss was 201 ± 216 mL. There was 1 intraoperative and 3 postoperative complications. One patient reported incomplete voiding with a postvoid residual under 100 mL, resolving within 1 week. Another reported increased bowel frequency that resolved within 1 month. CONCLUSION: Nerve-sparing is critical in the surgical treatment of parametrial endometriosis to minimize compromise of urinary and defecatory function.