Background: Cardiac catheterization (CC) is commonly performed following surgery for congenital heart defects (CHD) for diagnosis and intervention of residual lesions. Use of contrast during CC increases risk for acute kidney injury (AKI), although data are lacking. Our purpose was to evaluate the incidence and risk factors of AKI in pediatric patients who underwent CC within 14 days after CHD surgery with cardiopulmonary bypass (CPB). Methods: This was a retrospective chart review ofall children CHD surgery with CPB at a single Children';s Hospital. Patients known to have renal failure were excluded. Schwartz formula was used to calculate creatinine clearance for the first 72 hours following surgery and 72 hours following CC. pRIFLE criteria was used to categorize AKI as risk, injury and failure. Data were analyzed using SPSS software (Version 22, SPSS Inc. Chicago, IL) and expressed as mean ± SD and numbers (percentage). Results: Of 43 included patients, 85% were born full term; 44.2% were African-American and 39.5% were Caucasian; 22 (51.2%) had prior heart surgeries. At the time of CC, 40 (93%) patients remained on vasopressors and 11 (25.6%) were on ECMO. CC involved interventional procedures in 26 (60.5%) patients including balloon angioplasty in 13 (50%) and pulmonary artery stent placement in 12 (46.1%). Potentially nephrotoxic medications (aminoglycosides and vancomycin) were administered to 16 (38%) patients during the post-operative or post-CC period. The incidence of risk, injury and failure according to pRIFLE criteria in the postoperative and post-CC period are shown in [Table 1]. Incidence of risk and injury peaked on the day following surgery. AKI following CC was lower at all time points, compared to the early postoperative period. Risk category of AKI was the commonest, with incidence of 7.1% on the CC day, a peak of 16.7% on post-CC day-2 and rapid decrease thereafter. None of the patients had renal failure post CC and none required renal replacement therapy. At discharge, 36 (90%) patients had no AKI, 5% had risk and 2.5% each had kidney injury and failure. There were no significant differences between patients with (n= 8) and without (n= 34) AKI at any time within 72 hours of CC considering differences in age at time of surgery, gender, weight, body surface area, CPB time, aortic cross clamp time, days between surgery and CC and length of ICU stay [Table-2]. Conclusions: In pediatric patients, who are undergoing CHD surgery with CPB followed by CC within 14 days, contrast administration did not appear to be an additional risk factor for the development of AKI. AKI was relatively rare, mild and did not affect length of ICU or overall hospital stay. Further larger studies are needed to explore AKI in children with CHD.