Premature infants have uniformly demonstrated growth failure by 36 weeks postmenstrual age. In an evaluation of care quality, the authors tested the hypothesis that premature infants would grow adequately when they received more than 50 kcal/kg per day of parenteral nutrition. The study cohort consisted of 84 premature infants born at less than 30 weeks gestation. A computer software program was used to determine parenteral nutrition orders and establish a database. The database provided the nutrition and postnatal growth data. Successful growth was defined as weight greater than the 10th percentile for intrauterine growth. Energy intake exceeded 50 kcal/kg per day after the first day. The cohort weight and head circumference measurements remained above the 10th percentile of intrauterine growth through 36 weeks postmenstrual age. Infants demonstrated successful growth by remaining above the 10th percentile for the following: 4 of 12 (33%) with birth weights 501-750 g, 16 of 26 (62%) with birth weights 751-1,000 g, and 16 of 25 (64%) with birth weights 1,001-1,250 g. These differences were statistically greater than a large reference cohort (P < .0001). Length measurements declined below the 10th percentile of intrauterine growth at 36 weeks postmenstrual age. Postnatal growth failure is not an inevitable consequence of premature birth. The clinical evidence supports previous nutrient recommendations from the American Academy of Pediatrics. Promptly providing premature infants with parenteral nutrition, including calories greater than the basal energy requirement, can produce postnatal growth that remains above the 10th percentile of intrauterine growth.