OBJECTIVE--To evaluate clinical outcome after percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG) in patients of 75 or older who underwent either procedure between 1980 and 1987. SUBJECTS--93 patients aged 75-89 with angina pectoris class III-IV (Canadian Cardiovascular Society) who underwent PTCA and 81 patients aged 75-84 with angina class III-IV who underwent CABG. Follow up was 8.2 years in the PTCA group and 8.3 years in the CABG group. MAIN OUTCOME MEASURES--In-hospital complications and survival at follow up. RESULTS--Primary success rate for PTCA was 84% (78/93). Two patients died, two had emergency CABG, three had a myocardial infarction, and one had a cerebrovascular accident. PTCA failed in seven patients (five underwent elective CABG and two were treated conservatively). Median hospital stay was 4.3 days. Primary success rate for CABG was 63% (53/81). Six patients died, two had a cerebrovascular accident, eight had a myocardial infarction, 10 had a rethoracotomy, and four the adult respiratory distress syndrome. Median hospital stay was 14.2 days. In the PTCA group during follow up eight patients died, three had a non-fatal myocardial infarction, two had elective CABG, 10 had repeat PTCA, and four had recurrence of angina. Sixty four patients were free of angina (69%). In the CABG group during follow up eight patients died, one had a non-fatal myocardial infarction, six had PTCA, and three had recurrence of angina. Fifty seven patients were free of angina AP (70%). Actuarial survival after 10 years was 92% for PTCA and 91% for CABG. CONCLUSIONS--PTCA is safe in elderly patients. The complication rate is lower and hospital stay significantly shorter compared with CABG (p < 0.05). Long-term follow up showed no significant difference between PTCA and CABG.