Coronary angiography and exercise stress tests were performed in 91 consecutive patients under 60 years of age having either no or only mild angina pectoris with or without medication after a first myocardial infarction. Nine (10%) patients had angiographic high risk coronary artery disease defined as three vessel disease, left main stenosis, or proximal stenosis of the left anterior descending artery. Eighteen patients had a positive electrocardiographic exercise stress test including eight of the nine patients with angiographic high risk coronary artery disease. It may be concluded therefore that coronary angiography to detect high risk coronary artery disease in this group can be restricted to patients with a positive exercise stress test. This policy would obviate the need for about 80% of coronary angiograms performed in this age group.