In order to identify the risk factors which could predict outcome after coronary artery bypass grafting in patients with left ventricular dysfunction, 80 consecutive patients with an ejection fraction < or = 30%, who underwent isolated coronary artery bypass grafting at the authors' centre between January 1994 and May 1996 were evaluated. Preoperatively, mean(s.d.) ejection fraction was 27.1(3.8)%, 56 patients (70%) had angina, and 56(70%) were in New York Heart Association (NYHA) functional class III or IV. There were five operative deaths, with a hospital mortality rate of 6.3%. Significant risk factors for hospital death were NYHA class IV, preoperative ventricular arrhythmias and left ventricular end-diastolic volume index > 110 ml/m2. At mean follow-up of 15(7) (range 6-30) months, there were six late deaths, five of which were from cardiac causes. Actuarial survival rate at 2 years was 82(5)% and freedom from cardiac death 84(5)%. Risk factors for overall mortality from cardiac causes were preoperative grade 2 mitral regurgitation, associated with left ventricular dilatation, and renal dysfunction (creatininaemia > or = 180 micromol/l). At follow-up, mean ejection fraction was 37.5(8.4)%, and the overall functional status had improved: 12 patients (18%) had angina and eight (12%) were in NYHA class III and IV. Myocardial revascularization in patients with left ventricular dysfunction can be performed with acceptably low operative risk, good survival rate at 2 years, and functional status improvement. Patients with extensive ventricular dilatation, associated with significant mitral regurgitation, have a lower life expectancy and less functional benefits from coronary artery bypass grafting. These patients are better treated by cardiac transplantation.