This report presents an analysis of autopsy material from 3,942 cases of age 20 and older in whom the circle of Willis was scored for the severity and the extent of atherosclerosis. Several criteria were used to assess the effect of socioeconomic factors on cerebral atherosclerosis; these consisted of the financial hospital status of the patient, the place of residence, and occupation and physical activity. In the female patients it appeared that the indigent cases had a slightly higher prevalence of cerebral atherosclerosis than the private cases. In the males a difference in prevalence was found between urban and rural cases, the urban males showing higher scores. A comparison between a group of patients with mostly sedentary occupations and a group with more physically active occupations revealed no difference in atherosclerosis scores.