Recent data from the medical literature and other sources were used in an analysis of the cost-effectiveness of coronary artery bypass graft surgery (CABG) in symptomatic patients. Health effectiveness was expressed as the gain in quality-adjusted life expectancy, allowing for a range of subjective weights attached to symptomatic benefits. Costs included those of surgery, medical management of angina, and treatment of future myocardial infarctions. CABG appears to increase unadjusted life expectancy by 0.6 years in patients with two-vessel disease and 6.9 years in patients with left main coronary disease. Even in one-vessel disease, a gain in quality-adjusted life expectancy is estimated, owing to symptomatic benefits. For patients with severe angina, the estimated net cost per quality-adjusted year of life gained from CABG ranges from $3800 in left main disease to $30,000 in one-vessel disease. These figures compare favorably with those for other accepted medical therapies, such as treatment of moderate diastolic hypertension.