Serum vitamin A was determined in premature and term neonates by a specific spectrofluorometric method. Premature neonates (N = 42; gestational age = 32 +/- 0.4 weeks) had a serum vitamin A level (14.9 +/- 0.98 microgram/dl) significantly lower (P less than 0.001) than that of term neonates (N = 51; 22.4 +/- 0.99 microgram/dl). The vitamin A mean serum values of infants of 36 weeks' gestational age were not statistically different from those of the term neonates. Linear regression analysis for serum vitamin A values vs gestational age showed no significant correlation. A linear correlation (P less than 0.05), however, was found between serum vitamin A and serum protein protein concentrations, perhaps indicative of a lower concentration of retinol-binding protein. Since vitamin A is involved in the promotion of mucous-secreting cells, the premature neonate may be at greater risk than the term infant for diseases involving the mucosal epithelium, including necrotizing enterocolitis.