Operative and late postoperative results in 55 patients undergoing resection of a discrete, saccular type left ventricular aneurysm are described. All patients had occlusive lesions of either the left anterior descending or left main coronary artery, and 72 per cent had significant multivessel disease. Preoperative factors that correlated significantly with decreased long-term survival were age greater than 60 years, severe congestive heart failure, and subnormal cardiac output at rest. The primary determinant of long-term postoperative survival appears to be the functional state of residual myocardium after aneurysmectomy. The survival rate for patients with multivessel disease was not less than that of patients with isolated lesions of the left anterior descending coronary artery. The impact of simultaneous aorto-coronary bypass grafting on postoperative results in patients with multivessel coronary disease is discussed. An advantage to concomitant revascularization with aneurysmectomy cannot be statistically corroborated in this series. However, improvement in results since the routine application of bypass grafting in appropriate cases, the uniform operative survival of bypassed patients with triple vessel disease, and the relatively high frequency of myocardial infarction as a cause of late postoperative death suggest that bypass grafting in patients with multivessel disease should be combined with aneurysmectomy to maximally improve long-term prognosis.