Abstract Background Racial disparities in endometrial cancer have been reported in the United States, but trends and the underlying causes are not well understood. We aimed to examine the trends and contributing factors in racial disparities for causes of death among endometrial cancer patients. Method In this population-based cohort study, we identified 139 473 women diagnosed with first, primary endometrial cancer between 1992 to 2018 from the Surveillance, Epidemiology, and End Results Program. We used the “Fine and Gray” method to calculate the cumulative incidence of all-cause and specific-cause death. We used proportional subdistribution hazard (PSH) and cause-specific hazard (CSH) models to quantify the relative risk of Black–White disparities. We performed a mediation analysis to assess the contribution of potential factors to disparities. Results The cumulative incidence of all-cause death decreased in endometrial cancer patients, with estimates at 5 years of 26.72% in 1992-1996 and 22.59% in 2007-2011. Compared with White patients, Black patients persistently had an increased risk of death due to endometrial cancer (PSH hazard ratio [HR] = 2.05, 95% confidence interval [CI] = 1.90 to 2.22; CSH HR = 2.19, 95% CI = 2.00 to 2.40) and causes other than endometrial cancer (PSH HR = 1.23, 95% CI = 1.10 to 1.37; CSH HR = 1.46, 95% CI = 1.31 to 1.63). Grade, histological subtype, surgery utilization, and stage at diagnosis explained 24.4%, 20.1%, 18.4%, and 16.6% of the Black-White disparity in all-cause death, respectively. Conclusions Although the cumulative incidence of all-cause death decreased, the Black–White gaps persisted in patients with endometrial cancer. Grade and histological subtype had the greatest influence. More efforts are needed to address the disparities.