BACKGROUND: Endometrial cancer (EC) is the fourth most common cancer among Black women in the United States, a population disproportionately affected by aggressive nonendometrioid subtypes (e.g., serous, carcinosarcoma). To examine EC vulnerability among a wider spectrum of African descent populations, a comparison between Black women residing in different countries, rather than in the United States alone, is needed. METHODS: The authors analyzed 34,789 EC cases from Florida (FL) (2005-2018), Martinique (2005-2018), and Guadeloupe (2008-2018) based on cancer registry data. Age-adjusted incidence rates, incidence rate ratios (IRRs), and annual percent changes (APC) in trends were estimated for Black populations residing in the United States (non-Hispanic Blacks [NHB]) and Caribbean. The US non-Hispanic White (NHW) population was used as a reference. RESULTS: Caribbean Black women had the lowest rates for endometrioid and nonendometrioid subtypes. Nonendometrioid types were most common among US (FL) NHBs (9.2 per 100,000), 2.6 times greater than NHWs (IRR, 2.60; 95% confidence interval [CI], 2.44-2.76). For endometrioid EC, rates increased 1.8% (95% CI, 0.1-3.5) yearly from 2005 to 2018 for US (FL) NHBs and 1.2% (95% CI, 0.9-1.6) for US (FL) NHWs whereas no change was observed for Caribbean Blacks. For nonendometroid carcinomas, rates increased 5.6% (95% CI, 4.0-7.2) among US (FL) NHB, 4.4% (95% CI, 0.3-8.6) for Caribbean Black, and 3.9% for US (FL) NHW women (95% CI, 2.4-5.5). CONCLUSIONS: Lower rates of nonendometrioid EC among Caribbean Black women suggest that vulnerability for these aggressive tumor subtypes may not currently be an overarching African ancestry disparity. Most importantly, there is an alarmingly increasing trend in nonendometrioid across all populations studied, which warrants further surveillance and etiological research for this particular subtype. PLAIN LANGUAGE SUMMARY: We analyze population-based incidence rates and trends of endometrial cancer (EC) for African descent populations residing in different countries (i.e., United States, Martinique, Guadeloupe) to examine whether EC vulnerability among Black women is socio-environmental or more ancestry-specific in nature. The increased EC risk was not uniform across all Black women since the Caribbean had the lowest rates (for endometrioid and nonendometrioid histology subtypes). Regardless, from 2005 to 2018, there was an increasing trajectory of nonendometrioid EC for all groups, regardless of race.