Congenital heart disease is the most common birth defect in the United States, with an estimated frequency of approximately 12-14 of 1000 live births per year. Neonates with congenital heart disease often need palliative or corrective surgery requiring cardiopulmonary bypass during the first weeks of life. The neonate undergoing cardiopulmonary bypass surgery experiences a more profound metabolic response to stress than that seen in older children and adults undergoing surgery. However, compared with older children and adults, the neonate has less metabolic reserves and is extremely vulnerable to the negative metabolic impact induced by stress, which can lead to suboptimal wound healing and growth failure. There are complications associated with the metabolic derangements of neonatal surgery requiring cardiopulmonary bypass, including but not limited to acute renal failure, chylothorax, and neurological dysfunction. This article discusses the importance of nutrition and metabolic support for the neonate undergoing cardiopulmonary bypass and the immediate postoperative nutrition needs of such a patient. Also, this article uses a case study to examine the feeding methodology used at one particular institution after neonatal cardiac surgery. The purpose of the case study is to provide an illustration of the many factors and obstacles that clinicians often face in the provision and timing of nutrition support.