The natural history of coronary atherosclerotic heart disease was studied in a retrospective analysis of 160 patients, who underwent coronary arteriography from 1965 to 1969. All had at least one angiographically documented significant stenosis of more than 50%; the survivors were followed for at least 5 years and a maximum of 9 years. For the entire group, 5-year survival was 81%. Subdivided into single, double or triple vessel disease categories, the 5-year survival rates were 91, 85 and 63% respectively.