From the city center of Copenhagen, almost 20,000 people, 20 years of age and older, were randomly selected for examination after age and sex stratification. The participation rate was 72%. 231 persons responded affirmatively to a questionnaire concerning cerebrovascular disease. After neurological examination the diagnosis was confirmed in 115 cases. Adjusted on the basis of the age distribution of the Danish population (1976) the prevalence rate was calculated to be 651/100,000 for men and 385/100,000 for women. The frequency of myocardial infarction and hypertension was significantly higher in the stroke patients than in the study population. The risk factors: cigarette smoking, serum-cholesterol, and high-density-lipoprotein concentration, showed no significant differences between the patients and the study population. 44% of the patients had had their stroke more than 5 years before the prevalence date. In 41% of the patients, residual neurological signs could not be demonstrated, while 59% of the patients had neurological deficits of varying severity. 30% of the surviving patients were in gainful work or managed domestic activities as they had done before the stroke. Nearly 1/2 of the severely disabled patients were independent in self care. The age group above 80 years was under-represented in this study.