To study the effects of age on the results of coronary artery bypass grafting (CABG), 250 patients operated on from 1986 to 1989 were divided into two groups: 1) less than 65 years of age and 2) older than 65. Pre, intra and postoperative data collected in all patients included: sex, type and class of angina, associated diseases, previous myocardial infarction, previous CABG, left ventricular aneurysm, bypass time, aortic cross-clamp time, number of grafts per patient, need for prolonged inotropic support, postoperative complications, and mortality. A large number of elderly patients had unstable angina (20.3% vs 6.2%), post-infarction angina (10.1% vs 7.8%), angina at rest (10.1% vs 3.6%), peripheral vascular disease (8.4% vs 2.6%), required prolonged inotropic support (18.6% vs 3.1%), had major neurological complications (8.4% vs 0.1%) and perioperative myocardial infarction (5.0% vs 0.5%). Overall mortality was 3.6% but mortality rates were significantly higher in elderly patients (11.8% vs 1.0%). These data suggest that elderly patients have an increased risk of cardiac and neurologic morbidity and mortality. It appear that the increased morbidity and mortality is related to an increased susceptibility of the elderly to serious postoperative complications.