Early-stage endometrial cancer can be cured surgically using three techniques: laparotomy, laparoscopic surgery, and robotic-assisted surgery. In this retrospective study, we used 4 years of data from the Japanese Diagnosis Procedure Combination to analyze perioperative sequelae for each surgical procedure. Patients with early-stage endometrial cancer were classified into three groups: laparotomy, laparoscopic surgery, and robotic-assisted surgery. The number of robotic-assisted surgeries is increasing, but hospitals with low surgical volumes performed laparotomy at a rate of 57.6%, while hospitals with higher surgical volume tended to perform fewer laparotomies and more laparoscopic and robotic-assisted surgeries. Compared with the laparotomy group, the in-hospital risk ratios and 95% confidence intervals for postoperative sequelae were 0.28 (0.18–0.44) and 0.39 (0.23–0.69) in the laparoscopic and robotic-assisted surgery groups, respectively (P = 0.001 for all). Regarding blood transfusion treatment, the incidence rate ratios were lower for laparoscopic and robotic-assisted surgery than for laparotomy (P < 0.001 for all), even after multivariable analysis. In conclusion, in early-stage endometrial cancer, laparotomy had the highest incidence of perioperative sequelae compared to laparoscopic surgery and robotic-assisted surgery.