Pediatricians daily encounter children with systemic cyanosis. The numerous reasons for cyanosis in neonates and infants include pulmonary, hematologic, toxic, and cardiac causes. Congenital heart defects may cause cyanosis. Often, an obvious cardiac reason for cyanosis is decreased PBF; however, several congenital heart defects cause systemic cyanosis with increased PBF, such as TGA, truncus arteriosus, and TAPVR. Because neonates are discharged from the hospital soon after birth, this magnifies the importance of each physical examination. Pediatricians need to remain alert for children who have symptoms of increased PBF with or without cyanosis. With advances in the diagnosis and treatment of patients with CHD, corrective procedures can be performed at many ages.