Preoperative techniques to optimize a congenital heart surgery patient’s hemoglobin (Hgb) include anemia evaluation and treatment, a nutritional consult, and management of preexisting anticoagulation therapy. Erythropoietin stimulating agent (ESA) therapy may be considered in specific situations, such as renal insufficiency. The optimal preoperative Hgb value for patients with congenital heart disease (CHD) is unknown. Multiple studies have shown that perioperative restrictive transfusion strategies in pediatric patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are relatively safe. A CPB-associated coagulopathy may result secondary to hemodilution of platelets and coagulation factors, inflammation, hypothermia, and inadequately reversed heparin. Measures to mitigate excessive blood loss include CPB circuit miniaturization, circuit prime modifications, cell salvage, standardized transfusion algorithms, and point-of-care (POC) coagulation monitoring. Prothrombin complex concentrates (PCCs) and rVIIa are not recommended for the routine treatment of CPB-related bleeding in children.