Based upon the percentage of cases of IgA nephropathy (IgAN) in biopsy series, a lower prevalence has been assumed for African-Americans compared with Americans of European descent. This may be due to a racial difference in the basic underlying pathology of IgAN or to racial differences in patterns of referral and biopsy selection practices. Over the past decade (1985-1994), we have found similar incidences of IgAN in Caucasian and African-American children from Shelby County, Tennessee. The incidence was 3.0 cases per million per year for Caucasian and 5.7 cases per million per year for African-American children. IgAN may be more common in African-American children than previously appreciated. Population-based incidence studies will be necessary to determine whether or not our experience has become a more widespread phenomenon.