BACKGROUND: The number of elderly patients who may be candidates for coronary artery bypass graft (CABG) for severe coronary artery disease has increased. Cardiac surgery in the elderly is a high-risk procedure because many of these patients have concomitant systemic disease and other disabilities. HYPOTHESIS: The study was undertaken to evaluate mortality, risk indicators for death, and mode of death in younger and elderly patients during 5 years after CABG. METHODS: The study included all patients in western Sweden who underwent CABG without concomitant valve surgery and without previously performed CABG between June 1988 and June 1991. In all, 2,000 patients, of whom 953 (48%) were > or = 65 years, were divided into two age groups (< 65 years and > or = 65 years). RESULTS: Compared with the younger patients, the elderly had a relative risk of death of 2.3 (95% confidence interval 1.8-3.0). The increased risk of death in the elderly was significantly more marked in men, in patients with more severe angina pectoris, and in patients without a history of cerebrovascular diseases. The mode and place of death appeared similar regardless of age; neither was there marked difference in symptoms of angina pectoris among survivors 5 years after CABG. CONCLUSION: Compared with patients < 65 years, the elderly have more than twice as high a risk of death during the subsequent 5 years, and this risk is higher in men, in patients with severe symptoms of angina pectoris, and in those with no history of cerebrovascular disease.