BACKGROUND: There are limited data available to indicate whether oncological outcomes might be influenced by the uterine manipulator, which is used at the time of hysterectomy for minimally invasive surgery in patients with endometrial cancer. The current evidence derives from retrospective studies with limited sample sizes. Without substantial evidence to support its use, surgeons are required to make decisions about its use based only on their personal choice and surgical experience. OBJECTIVE: To evaluate the use of the uterine manipulator on oncological outcomes after minimally invasive surgery, for apparent early-stage endometrial cancer. STUDY DESIGN: We performed a retrospective multicentric study to assess the oncological safety of uterine manipulator use in patients with apparent early-stage endometrial cancer, treated with minimally invasive surgery. The type of manipulator, surgical staging, histology, lymphovascular space invasion, International Federation of Gynecology and Obstetrics stage, adjuvant treatment, recurrence, and pattern of recurrence were evaluated. The primary objective was to determine the relapse rate. The secondary objective was to determine recurrence-free survival, overall survival, and the pattern of recurrence. RESULTS: A total of 2661 women from 15 centers were included; 1756 patients underwent hysterectomy with a uterine manipulator and 905 without it. Both groups were balanced with respect to histology, tumor grade, myometrial invasion, International Federation of Gynecology and Obstetrics stage, and adjuvant therapy. The rate of recurrence was 11.69% in the uterine manipulator group and 7.4% in the nomanipulator group (P<.001). The use of the uterine manipulator was associated with a higher risk of recurrence (hazard ratio, 2.31; 95% confidence interval, 1.27e4.20; P¼.006). The use of uterine manipulator in uterus-confined endometrial cancer (International Federation of Gynecology and Obstetrics [FIGO] IeII) was associated with lower disease-free survival (hazard ratio, 1.74; 95% confidence interval, 0.57e0.97; P¼.027) and higher risk of death (hazard ratio, 1.74; 95% confidence interval, 1.07e2.83; P¼.026). No differences were found regarding the pattern of recurrence between both groups (chi-square statistic, 1.74; P¼.63). CONCLUSION: In this study, the use of a uterine manipulator was associated with a worse oncological outcome in patients with uterusconfined endometrial cancer (International Federation of Gynecology and Obstetrics IeII) who underwent minimally invasive surgery. Prospective trials are essential to confirm these results.