Inadequate nutritional support in infants with congenital heart disease recovering from heart surgery can impact on morbidity and growth. We sought to determine nutritional support and growth patterns for infants <1y undergoing surgery for congenital heart lesions from 11/94 to 02/95 and factors associated with positive daily weight gains during ward recovery. Data were collected from the medical records of 24 infants with median age 2.7 m(range, 1d to 9.1m) at surgery for transposition of the great arteries in 9, atrio-ventricular septal defect 4, hypoplastic left heart syndrome 2, truncus arteriosus 2, pulmonary atresia 2, tetralogy of Fallot 2, ventricular septal defect in 2 and total anomalous pulmonary venous return in 1. Median days in ICU was 4d (2d to 20d). The median days on ward was 6d (3d to 21d). Average daily weight gain on the ward was -20 ± 47 gm/day, with net positive gain in 8 (36%), net loss in 14 (64%) and unknown in 2. Mean daily weight gain was related to feeding type: formula only, 2 ± 30 gm/day; breast and formula, -27 ± 48 gm/day; and breast only -44 ± 30 gm/day(p=0.003). Patients who met a greater percentage of their energy requirements by discharge had higher daily weight gain (r=0.57; p=0.05). Mean daily weight gain was not related to type of cardiac lesion or length of stay.Conclusions: Greater attention to achieving energy requirements for infants during recovery from cardiac surgery is necessary. Weight gain is suboptimal, and this is related to feeding type. Caloric supplementation is needed for infants who are breast fed.