BACKGROUND We compared long-term results of coronary artery bypass grafting between 1976 and 1988 in 176 patients 40 years old or younger with a matched control group of 176 patients 25 to 30 years older. METHODS Mean age was 37.4 +/- 2.7 years (+/- standard deviation) in the study group and 64.2 +/- 2.9 years in the control group. Matching criteria were age, sex, left ventricular ejection fraction, number of bypass grafts, and year of operation. RESULTS The study group had more smokers (p = 0.000) and more patients with hypercholesterolemia (p = 0.026), unstable angina (p = 0.003), and preoperative myocardial infarction (p = 0.009); fewer patients had hypertension (p = 0.000) and diabetes (p = 0.005) in this group than in the control group. The internal mammary artery was used in 31% of the study patients and in 30% of the controls. The actuarial survival rates after 5, 10, and 15 years were 92%, 86%, and 72% in the study group and 92%, 86%, and 66% in the control group (p = 0.202). Young age was a predictor of cardiac reoperation. CONCLUSIONS Late survival is similar for young and older patients, but the reintervention rate is higher in the younger group. The absence of unstable angina, a left ventricular ejection fraction greater than 0.45, and the use of internal mammary artery grafts increase survival in all patients.