Study Objective Surgery for deep infiltrating and bowel endometriosis involves risks of organ injury, reoperation, and prolonged hospital stay. Surgical outcomes following surgery for ovarian endometriosis (endometrioma, OMA) are currently unknown. The objective of this study was to evaluate perioperative outcomes of premenopausal women undergoing cystectomy or oophorectomy for OMAs compared to other benign ovarian neoplasms. Design Retrospective cohort study. Setting Vizient Clinical Database, which contains information from 580 participating hospitals across the United States. Patients or Participants Patients ages 18-50 who underwent ovarian cystectomy or oophorectomy for benign indications 2010-2020 were identified. OMAs included ICD-9/10 codes for ovarian endometriosis. We excluded patients who received concomitant hysterectomy or obstetric or oncologic care. Interventions We abstracted clinical data, including surgical route, length of stay, and 30-day postoperative complication rates. Procedures performed for OMA were compared to other surgical indications. Measurements and Main Results We identified 58,874 patients who underwent oophorectomies (10,464 OMAs vs. 48,410 for other indications) and 125,911 ovarian cystectomies (30,058 OMAs vs. 95,853 other). During oophorectomy, patients with OMAs were less likely to undergo minimally invasive surgery (63% vs. 67%, p<0.001) and more likely to require conversion to laparotomy (4.3% vs. 3.4%, p<0.001) and extended hospitalization 2+ days (40% vs. 37%, p<0.001). Among women undergoing cystectomy, conversion to laparotomy (5.3% vs. 3.3%, p<0.001) and readmission (8.5% vs. 7.2%, p<0.001) were more common with OMAs. In multivariable logistic regression, OMA predicted conversion to laparotomy during oophorectomy (aOR 1.3, 95% CI=1.1-1.4) and cystectomy (aOR 1.6, 95% CI=1.5-1.7). Urinary tract injury was infrequent and occurred more often during surgery for indications other than endometriosis (oophorectomy 1.7% vs. 0.95%, cystectomy 0.74% vs. 1.3%, all p<0.001). Bowel injury was exceedingly rare (0.01% of all procedures). Conclusion We present population-level data demonstrating that patients undergoing ovarian cystectomy or oophorectomy for endometriomas had higher rates of perioperative adverse events, including conversion to laparotomy, extended hospital stay, and readmission. Surgery for deep infiltrating and bowel endometriosis involves risks of organ injury, reoperation, and prolonged hospital stay. Surgical outcomes following surgery for ovarian endometriosis (endometrioma, OMA) are currently unknown. The objective of this study was to evaluate perioperative outcomes of premenopausal women undergoing cystectomy or oophorectomy for OMAs compared to other benign ovarian neoplasms. Retrospective cohort study. Vizient Clinical Database, which contains information from 580 participating hospitals across the United States. Patients ages 18-50 who underwent ovarian cystectomy or oophorectomy for benign indications 2010-2020 were identified. OMAs included ICD-9/10 codes for ovarian endometriosis. We excluded patients who received concomitant hysterectomy or obstetric or oncologic care. We abstracted clinical data, including surgical route, length of stay, and 30-day postoperative complication rates. Procedures performed for OMA were compared to other surgical indications. We identified 58,874 patients who underwent oophorectomies (10,464 OMAs vs. 48,410 for other indications) and 125,911 ovarian cystectomies (30,058 OMAs vs. 95,853 other). During oophorectomy, patients with OMAs were less likely to undergo minimally invasive surgery (63% vs. 67%, p<0.001) and more likely to require conversion to laparotomy (4.3% vs. 3.4%, p<0.001) and extended hospitalization 2+ days (40% vs. 37%, p<0.001). Among women undergoing cystectomy, conversion to laparotomy (5.3% vs. 3.3%, p<0.001) and readmission (8.5% vs. 7.2%, p<0.001) were more common with OMAs. In multivariable logistic regression, OMA predicted conversion to laparotomy during oophorectomy (aOR 1.3, 95% CI=1.1-1.4) and cystectomy (aOR 1.6, 95% CI=1.5-1.7). Urinary tract injury was infrequent and occurred more often during surgery for indications other than endometriosis (oophorectomy 1.7% vs. 0.95%, cystectomy 0.74% vs. 1.3%, all p<0.001). Bowel injury was exceedingly rare (0.01% of all procedures). We present population-level data demonstrating that patients undergoing ovarian cystectomy or oophorectomy for endometriomas had higher rates of perioperative adverse events, including conversion to laparotomy, extended hospital stay, and readmission.