Background: Postoperative increase in serum creatinine (SCr) is the known to be one of the main determinants for short-term mortality after coronary artery bypass graft (CABG) surgery. However, its association with long-term mortality has not been properly evaluated. Methods and results: We prospectively enrolled 572 patients who underwent CABG from January 2000 to June 2004. Patients with end-stage renal disease were excluded. The relationship between baseline/change in renal function and long-term mortality was studied. Patients were stratified by 4 groups according to the presence of underlying chronic renal failure (CCr<60ml/min) and perioperative acute renal failure (ARF) defined as 50% increase in SCr from baseline. Median duration of follow-up was 4.4짹1.5 years. Survival analysis revealed that the patients with ARF had the worst prognosis (Figure). By Cox proportional hazards model, perioperative ARF was an independent predictor of long-term mortality (HR, 5.71; 95% CI, 2.98 to 10.93). Low ejection fraction (LVEF<50%) and age were also predictors of long-term mortality. Conclusion : Perioperative ARF is an independent predictor of long-term mortality irrespective of underlying renal function in patients with CABG.