With the aim of examining the possible association between atherosclerosis of the aorta and renal scarring, an autopsy study comprising 81 men and 43 women was performed. The per cent intimal surface involved with atherosclerosis in the aorta above the renal arteries was determined by morphometry, and the per cent surface profile of the kidney affected by scarring was measured microscopically in a standardized fashion. In addition, the following variables were determined: the age of the patient, diameter of the renal artery ostia, weight of the kidneys, heart weight, presence or absence of signs of sustained myocardial infarction, highest measured systolic blood pressure and the number of macroscopic renal scars. The data were subjected to both simple correlation and multiple regression analyses. In both men and women there was a significant simple correlation between the degree of atherosclerosis in the aorta and the extent of subcapsular microscopic renal scarring. In men, the prime importance of aortic atherosclerosis for microscopic renal scarring was supported in the multiple regression analysis. In women, this analysis showed that age was the determining predictive factor for microscopical renal scarring. The results may be taken to support the hypothesis that micro-embolism from an atherosclerotic aorta may be a cause of microscopic subcapsular scars in the kidneys.