This study compared growth of a group of very low birth weight infants fed a formula specifically developed for such infants (Formula) with another group fed expressed breast milk (EBM). The Formula contained 2.4 g/dl of protein (lactalbumin:casein ratio, 60:40); 4.1 g/dl of fat (40% medium-chain triglycerides); 8.8 g/dl of carbohydrates; and 81 kcal/dl, with more calcium, phosphorus, and electrolytes than are in human milk. Premature babies with birth weights between 1,200 and 1,500 g and gestational age less than 36 weeks were eligible for the study and were fed either pooled EBM or Formula until they reached a weight of 1,800 g. Twenty infants fed EBM and 19 infants fed Formula completed the trial. Weight gain was faster in the Formula-fed infants after a caloric intake of 100 kcal/kg/day was achieved (Formula 27.7 g/day vs. EBM 17.2 g/day; p less than 0.001). Time to reach 1,800 g was 27 days for the Formula group and 39 days for those on EBM (p less than 0.001). Increments in head circumference and skinfold thickness were also greater in the Formula-fed group. Laboratory studies in the two groups of infants showed higher alkaline phosphatase levels, which were not due to vitamin D deficiency, in the EBM-fed infants.