The influence of administration of approximately 90 mg. of iron per day as ferrous sulfate was studied in 23 normal infants averaging 14 months of age. Comparison of hematologic values observed at the start and end of a 6-week therapeutic course were made. The results were compared with hematologic values of normal infants of the same age. Reports by other investigators that a significant rise in the hemoglobin concentrations in normal infants can be achieved, with a therapeutic course of iron given orally were confirmed. Cytologic manifestations of "physiologic" anemia of infancy were not altered significantly after 6 weeks of therapy. These included the mean cell volume (microcytosis) and mean corpuscular hemoglobin concentration (hypochromasia). The chemical manifestations of iron deficiency previously reported in a normal infant population were confirmed; these included, compared to normal values in adult males, hypoferremia, hypercupremia, reduced saturation of the total serum iron binding capacity and increased free erythrocyte protoporphyrin. As indicated previously, these values suggest that in addition to the mild degree of iron deficiency anemia in the normal infant, there is depletion of his iron stores. The short course of iron therapy employed in this study did not significantly alter the chemical manifestations of depleted iron stores.