A correction is made of prostate cancer incidence rates based on data from the Surveillance, Epidemiology, and End Results Program of the United States National Cancer Institute. Unlike conventional incidence rates reported by the Program, corrected rates remove from the population the estimated number already diagnosed with the disease. The corrected rates reflect the average prostate cancer risk for men in the at-risk population. Because of the high incidence of and relatively good survival for prostate cancer, the prevalence of this disease is high. Corrected prostate cancer incidence rates were higher in magnitude, particularly in older age groups and among Black men. For example, in 1997 for Whites, the corrected rates were 3.8 percent higher in cases aged 60-69 years, 9.3 percent higher in cases aged 70-79, and 13.1 percent higher in cases aged 80 or more. Corresponding percentages for Blacks were 5.9, 18.9, and 16.9 percent, respectively. Percent changes over calendar time were very similar between corrected and uncorrected prostate cancer incidence rates according to age and race (White and Black). Failure to account for high levels of prostate cancer prevalence in conventional incidence rates of the disease results in underestimation of the rates but little temporal difference in the trends.