Background: Acute kidney injury (AKI) occurs in approximately 40% of children undergoing cardiac surgery and is a risk factor for morbidity and mortality. Such injury leads to several complications, including fluid and electrolyte disturbances. Objective: To determine prevalence of acute kidney injury in pediatric patients with congenital heart disease following open heart surgery. Patients and Methods: We conducted a case control study on 20 patients with congenital heart disease (10 males and 10 females) with mean age of 3.39 ± 1.17 years old, and a range from 1 to 5 years old. They were recruited from Pediatric Cardiothoracic Unit, Zagazig University Hospital and 20 sex and age matched healthy children worked as control group. Results: The mean age of our patients was 3.39 ± 1.17 years old with a range from 1 to 5 years. 50% were males and 50 % were females with no statistically significant difference between both groups regarding age and sex. about 1/3 of the studied group had ASD (30 %), while 1/4 of them had Fallot tetralogy (25 %), and only 15% of them had VSD, subaortic membrane and PM + VSD. The mean serum creatinine level was 0.8 ± 0.15mg/dl, with a range from 0.22 - 0.9 mg/dl. 70% of the patients had no acute kidney injury, 15% developed AKI stage 1 and 15% developed stage 2 AKI. In addition, all patients with AKI needed dialysis. Conclusion: Present study identified that high percentage of pediatric patients with congenital heart disease following open-heart surgery developed acute kidney injury.