A study was undertaken to estimate the incidence of glomerular sclerosis in the normal population in Hong Kong. The percentage glomerular sclerosis in 100 cadavers without clinical evidence of kidney disease or hypertension was determined by histologic examination of the kidneys. The mean percentage values in the normal population at all age groups were calculated based on this sample. The subcapsular cortical area generally had a higher proportion of sclerotic glomeruli than the deeper cortex. Statistical analysis showed that 95% of the normal population up to 40 years of age would be expected to have less than 6% sclerotic glomeruli. After the age of 55, the upper limit containing 95% of the normal population would exceed 10% sclerosis. A broad scatter of observed percentage glomerular sclerosis was present in the elderly after the age of 70 years. The data obtained provide the baseline values of glomerular scarring that would allow age-related involutional changes to be distinguished from those due to disease.