Abstract Endometrial cancer (EC) incidence is on the rise. Although early-onset endometrial cancer (EOEC; age at diagnosis <50 years) is relatively uncommon, the incidence of EOEC has been reportedly increasing in recent decades. However, the rising EOEC has not been thoroughly described with regard to the racial and ethnic disparities and compared with late-onset EC (age at diagnosis ≥50 years). We used the Cancer in North America (CiNA) Analytic File, 1995-2018, from the North American Association of Central Cancer Registries, which allowed us to examine trends in invasive EC incidence by racial and ethnic groups and by age at diagnosis. We found striking differences for demographic and tumor characteristics as well as racial and ethnic patterns and time trends in EC incidence between EOEC and late-onset EC. The faster increases in EOEC incidence rates, especially among non-White women, mirror similar observations in other cancers, pointing to a possible link with rising obesity epidemic in younger generations.