The timing of operative intervention in patients with less severe angina is a point of some dispute at present. It is, however, apparent that certain categories of patients have improved survival after elective bypass surgery. These categories include patients with left main coronary stenosis, triple vessel disease with modestly impaired ventricular function, and possibly other clinically defined high risk patients. The remaining patients with mild, symptomatic coronary disease, it would appear, can afford to defer operative intervention until such time as symptoms worsen and require palliation.