Background: Near-infrared spectroscopy (NIRS) is a useful non-invasive tool for monitoring infants undergoing cardiac surgery. In this study, we aimed to determine the NIRS values in cyanotic and acyanotic patients who underwent corrective cardiac surgery for congenital heart diseases. Methods: Thirty consecutive infants who were operated on with the diagnosis of ventricular septal defect (n=15) and tetralogy of Fallot (n=15) were evaluated retrospectively. A definitive repair of the underlying cardiac pathology was achieved in all cases. A total of six measurements of cerebral and renal NIRS were performed at different stages of the perioperative period. The laboratory data, mean urine output and serum lactate levels were evaluated along with NIRS values in each group. Results: The NIRS values differ in both groups, even after the corrective surgical procedure is performed. The recovery of renal NIRS values is delayed in the cyanotic patients. Conclusion: Even though definitive surgical repair is performed in cyanotic infants, recovery of the renal vasculature may be delayed by up to two days, which is suggestive of a vulnerable period for renal dysfunction.