Importance: Minimally invasive laparoscopic surgery (MILS) for endometrial cancer reduces surgical morbidity compared with a total abdominal hysterectomy. However, only a minority of women with early-stage endometrial cancer undergo MILS. Objective: To evaluate the association between the Danish nationwide introduction of minimally invasive robotic surgery (MIRS) and severe complications in patients with early-stage endometrial cancer. Design, Setting, and Participants: In this nationwide prospective cohort study of 5654 women with early-stage endometrial cancer who had undergone surgery during the period from January 1, 2005, to June 30, 2015, data from the Danish Gynecological Cancer Database were linked with national registers on socioeconomic status, deaths, hospital diagnoses, and hospital treatments. The women were divided into 2 groups; group 1 underwent surgery before the introduction of MIRS in their region, and group 2 underwent surgery after the introduction of MIRS. Women with an unknown disease stage, an unknown association with MIRS implementation, unknown histologic findings, sarcoma, or synchronous cancer were excluded, as were women who underwent vaginal or an unknown surgical type of hysterectomy. Statistical analysis was conducted from February 2, 2017, to May 4, 2018. Exposure: Minimally invasive robotic surgery, MILS, or total abdominal hysterectomy. Main Outcomes and Measures: Severe complications were dichotomized and encompassed death within 30 days after surgery and intraoperative and postoperative complications diagnosed within 90 days after surgery. Results: A total of 3091 women (mean [SD] age, 67  years) were allocated to group 1, and a total of 2563 women (mean [SD] age, 68  years) were allocated to group 2. In multivariate logistic regression analyses, the odds of severe complications were significantly higher in group 1 than in group 2 (odds ratio [OR], 1.39; 95% CI, 1.11-1.74). The proportion of women undergoing MILS was 14.1% (n = 436) in group 1 and 22.2% in group 2 (n = 569). The proportion of women undergoing MIRS in group 2 was 50.0% (n = 1282). In group 2, multivariate logistic regression analyses demonstrated that a total abdominal hysterectomy was associated with increased odds of severe complications compared with MILS (OR, 2.58; 95% CI, 1.80-3.70) and MIRS (OR, 3.87; 95% CI, 2.52-5.93). No difference was found for MILS compared with MIRS (OR, 1.50; 95% CI, 0.99-2.27). Conclusions and Relevance: The national introduction of MIRS changed the surgical approach for early-stage endometrial cancer from open surgery to minimally invasive surgery. This change in surgical approach was associated with a significantly reduced risk of severe complications.