Age has been identified as an independent risk factor for coronary artery bypass grafting (CABG). We evaluated, therefore, the perioperative phase and long-term prognosis of all patients over the age of 64 (n = 80), who had been operated on for coronary heart disease at the University Hospital of Basel/Switzerland between 1979 and 1983. These elderly subjects were compared to 80 patients, 50 to 60 years old at the time of CABG, who were matched for degree of angina pectoris, coronary artery disease, left ventricular ejection fraction, sex and year of operation (matched-pairs analysis). Evaluation of long-term prognosis was based on regular clinical controls and on a questionnaire, sent to the patients in June 1984. During the perioperative phase 3 patients over 64 died versus 0 in the group of patients 50-60 years old. There were more complications in the older group (perioperative myocardial infarction 10 vs. 4, pulmonary embolism 2 vs. 0, cerebro-vascular insult 4 vs. 0). Three vs. one permanent pacemaker had to be implanted for irreversible AV-block. The difference in hospital stay, 21 vs. 19 days, was not significant. The cumulative survival rate was in both groups 95% after one year and 86 vs. 92% 5 years after CABG (difference not significant), despite the fact that significantly more elderly patients have had myocardial infarction prior to CABG. After an average follow-up of 28 months, 72% vs. 60% were without thoracic pain; 63 vs. 49% considered themselves in a good overall condition.(ABSTRACT TRUNCATED AT 250 WORDS)