Congenital heart defects are one of the most common malformations in the neonatal stage, with a global prevalence between 8-9.5 per 1,000 newborns. Patients with congenital heart disease have mul-tiple risk factors for developing kidney failure, either associated with the intrinsic pathophysiological changes of congenital heart disease or its treatments, especially cardiac surgery with cardiopulmonary bypass. Acute kidney injury (AKI) after cardiac surgery is frequent and it is associated with adverse, acute, and potential long-term kidney consequences. Considering that these patients are at an eleva-ted risk for postoperative AKI and possible long-term kidney damage, it is crucial to prioritize stra-tegies aimed at primary prevention, early detection, and secondary prevention of AKI. The objective of this report is to review the pathophysiology of AKI after cardiac surgery with cardiopulmonary bypass, its acute complications, and the long-term kidney consequences, proposing a structured pro-tocol for kidney follow-up.