Objective: To evaluate the impact of obesity on the outcomes of surgical treatment for endometrial cancer in general and also comparing laparoscopic and open abdominal approach. Design: Retrospective case-control study (Canadian Task Force classification II-1). Setting: Obstetrics and Gynecology Department, University of Insubria, Varese, Catholic University of the Sacred Heart, Rome, International School of Surgical Anatomy, Sacred Heart Hospital, Negrar, and Sant'Orsola-Malpighi Hospital, Bologna, Italy. Patients: Data of consecutive patients who underwent surgery for endometrial cancer in 4 centers were reviewed. Univariate and multivariable analyses were performed. Adjustment for potential selection bias in surgical approach was made using propensity score (PS) matching. Interventions: Laparoscopic or open surgical treatment for endometrial cancer. Measurements and Main Results: A total of 1266 patients were included, including 764 in the laparoscopy group and 502 in the open surgery group. A total of 391 patients (30.9%) were obese, including 238 (18.8%) with class I obesity, 89 (7%) with class II obesity, and 64 (5.1%) with class III obesity. The total number of complications, risk of wound complications, and venous thromboembolic events were higher in obese women compared with nonobese women. Blood transfusions, incidence/severity of postoperative complications, and postoperative hospital stay were significantly higher in the open surgery group compared with the laparoscopy group, irrespective of obesity. These differences remained significant in both multivariable analysis and PS-matched analysis. The percentage of patients who received lymphadenectomy declined significantly in patients with BMI ≥40 in both the laparoscopy and open surgery groups. Conversions from the initially intended minimally invasive approach to open surgery were 1.1% to 2.2% for women with BMI