To study the results of bypass surgery in young adults, 221 patients undergoing myocardial revascularisation aged 40 or less (1979-1989) were reviewed. The study included 200 men and 21 women. Mean age was 36.2 years. Risk factors were essentially cigarette smoking (69.6%) and hyperlipidaemia (52%). One-hundred and eighteen patients (53.4%) had a history of previous myocardial infarction (MI) and 16 were operated on after an episode of preinfarction angina. One-hundred and twenty-nine patients had three-vessel disease, 59 had double-vessel disease and 33 single-vessel disease. Twenty-three had left main stem coronary artery lesions. Four-hundred and forty-six saphenous vein grafts and 79 internal mammary artery grafts were performed, an average of 2.3 grafts per patient. Operative mortality was 2.7% (6 patients). Deaths were caused in 4 cases by MI. Twelve patients (5.5%) had a non fatal perioperative MI. One-hundred and ninety-nine patients were followed up for a mean of 7.4 years (4838 patients-years). Seventeen late deaths occurred. Six were from cardiac causes. Overall survival was 84% at 9 years. Five patients underwent cardiac reoperation at a mean interval of 6.4 years after the primary procedure. Eighty-five% of patients were free of angina and 11.5% were in an improved condition. In conclusion, coronary revascularisation can be performed at a reduced risk in younger patients. Long-term prognosis seems similar to that of the overall group of patients undergoing bypass surgery.