We have demonstrated considerable variability in the volumes of different glomeruli in given individuals (individual glomerular volume: IGV) in a stereologic study of kidneys at forensic autopsy performed to investigate sudden or unexpected death in people without manifest kidney disease. We review some important associations of IGV by subject characteristics and by ethnic groups. IGVs were measured by the Cavalieri method in 30 glomeruli in each of 111 adult males who belonged to 4 ethnic groups, i.e. US Whites, African-Americans, Africans from Senegal, and Australian Aborigines. Correlations of pooled IGV values with certain subject characteristics were evaluated in the US Whites. Pooled IGV data were compared in subjects across the 4 ethnic groups. In US Whites, mean IGV and its variance were greater with higher age, lower nephron number, lower birth weight, and with gross obesity, hypertension and cardiovascular death. In comparisons by ethnic group, mean IGV and IGV ranges were higher in African-Americans and Australian Aborigines than in US Whites and African Senegalese subjects. We conclude that glomerular enlargement with volume heterogeneity marks more advanced age, relative nephron deficiency, lower birth weight, obesity, hypertension, and advanced cardiovascular disease. The findings in African-Americans and Australian Aborigines suggest that larger IGVs and volume heterogeneity might mark populations with accentuated susceptibility to hypertension and kidney disease, but the data need to be further examined in the context of the determining characteristics defined in the US Whites.