In the United States, endometrial carcinoma incidence rates, uncorrected for hysterectomy prevalence, are higher among white women than black women. We estimated corrected endometrial carcinoma rates by racial/ethnic groups and age (30-74 years) for 1992-2000 using data from the Surveillance, Epidemiology, and End Results program and the Behavioral Risk Factor Surveillance Survey. Hysterectomy prevalence was higher among black women than among Hispanic and white non-Hispanic women. Correcting for hysterectomy prevalence increased age-adjusted endometrial carcinoma rates per 10(5) woman-years from 29.2 to 48.7 (66.8% increase) overall, from 14.6 to 28.5 (95.3% increase) in blacks, from 18.8 to 29.6 (57.6% increase) in Hispanics, and from 33.2 to 54.9 (65.1%) in white non-Hispanics. This correction reduced the rate ratio for white non-Hispanics compared with blacks from 2.27 to 1.93. Among blacks but not Hispanics or white non-Hispanics, the endometrial carcinoma risk factors of obesity and diabetes were more prevalent among hysterectomized than nonhysterectomized women. Failure to correct for hysterectomy prevalence may lead to underestimates of endometrial carcinoma risk, especially among blacks. The high prevalence of hysterectomy among blacks with strong endometrial cancer risk factors may partly account for lower cancer rates in this group.