Vitamin A has been shown to be important in immunity and in differentiation of epithelial tissues. Serum concentrations of vitamin A (retinol) were measured at birth, in 54 preterm and 24 full term infants. Vitamin A concentrations were significantly lower in the preterm compared to the full term infants (9.81 +/- 0.58 micrograms/dl v. 15.58 +/- 1.00 micrograms/dl, P = 0.0001). Serum retinol and birth weight were positively correlated (r = 0.39, P = 0.0004); however, there was no correlation between maternal and infant vitamin A concentrations. The initially reduced vitamin A levels in the preterm infants were not associated with respiratory distress syndrome or pneumonia.