A 1-h basal collection of gastric secretions was taken from 14 healthy full-term infants (group I) and 10 premature infants (group II). Simultaneously, acid and intrinsic factor (IF) secretion was measured. In an additional group of 19 full-term infants (group III), 16 had IF detectable in their gastric secretions immediately at birth. Volumes of gastric juice (ml/kg/h) and IF secretion (ng/ kg/h) were similar for group I and group II infants. Acid secretion (mEq/kg/h) was significantly less in group II (p < 0.01). There was a linear correlation between acid secretion (mEq/kg/h) and IF secretion (ng/kg/h) for group I (r = 0.85, p < 0.001). There was no correlation between the values for the premature infants in group II. The study documents that the parietal cell of the premature infant has the same capacity to secrete IF as the cell of the more mature infant. It also demonstrates the presence at birth of IF in gastric secretions, which suggestsin uterosecretion and independence from enteral feeding for stimulation.