Aim To compare the early outcomes after coronary artery bypass grafting(CABG)among different aged groups.Method 4 303 patients were underwent isolated CABG in our hospital.All of the patients were divided into 4 groups according to the age:Group A(≤45 years),Group B(46~60 years),Group C(61~74 years)and Group D(≥75 years).The preoperative risk factors,mortality and complications were analyzed between each group.Results The factors that hypertension,the incidence of mild mitral insufficiency or aortic insufficiency,preoperative blood creatinine,the proportion of saphenous vein to left anterior descending artery,ventilation time,intensive care unit stay were lower in group A and B than those in group C and D.Whereas the proportion of cardiopulmonary bypass(CPB)and total arterial bypass grafting were higher in group A and B than those in group C and D.The mortality in group A(0.35%)and B(1.52%)was significant lower than that in group C(2.62%)and D(5.45%).The incidence of complications of atrial fibrillation(8.18%)and low cardiac output syndrome(3.18%)in group D were maximum.Conclusion Saphenous vein to left anterior descending artery,age and CPB are the independent risk factors of operative mortality.The number of diseased vessels,the proportion of total arterial bypass grafting,mitral insufficiency,aortic insufficiency and preoperative blood creatinine are contributory factors to operative death.Postoperative renal insufficiency may be relative to preoperative diabetes mellitus and blood creatinine.