Acute renal failure (ARF) is a major complication in infants who undergo cardiac surgery. The aim of this investigation was to identify possible risk factors for ARF and mortality in this patients group. Out of 64 patients, 21 (32.8%) cases developed acute renal failure and overall mortality rate was 25%. The mortality rate was higher in the infants who developed ARF than those who did not (66.7% and 4.7%, respectively, p<0.05). Also, ARF was positively correlated with mortality (r:0.70, p<0.0001). The nonsurvivors had lower mean serum albumin than did the survivors (p<0.05), and serum albumin level was negatively correlated with mortality (r= -0.34,p<0.05). For the patients with serum albumin level <3.5 g/dL, the unadjusted odds ratio for mortality was 4.3 (CI 95%:1.05-17.86). Total bypass time and aorta clamping time were significantly longer in the nonsurvivor group than in the survivor group (p<0.05 for both). In conclusion, the significant risk factors for mortality in these patients were development of ARF, low serum albumin level, and long total bypass and aorta clamping times, which may be predictive of poor prognosis.