Coronary angiography was performed in a total of 3,696 patients at the Institute for Clinical and Experimental Medicine from 1971 to 1980. From this number 720 were in the subsequent period treated surgically for ischaemic heart disease (IHD). In the majority of them myocardial revascularization was performed using saphenous vein aortocoronary bypass graft and in 7% resection of left ventricular aneurysm was carried out, either separately or together with the aortocoronary bypass. The remaining patients with IHD were treated medically. All patients were followed up for a period ranging from 1 to 10 years (mean 50 months). In most of the patients there was symptomatic improvement and increased tolerance of physical exercise. Among patients with double- and triple-vessel disease there was higher survival in those treated surgically. There was no difference in survival between surgically and medically treated patients with single-vessel disease and patients after aneurysmectomy. Neither was there a marked difference in survival symptoms, exercise tolerance and the occurrence of postoperative myocardial infarction between patients with preoperative MI and those without it. No influence was found of surgical treatment of IHD on the occurrence of sudden death.