Objectives of this research were to compare iron bioavailabilities from infant rice cereals fortified with either electrolytic iron (EI) or ferrous sulfate (FS) and to evaluate the piglet as a model for iron bioavailability studies. Iron bioavailability was assessed by hemoglobin repletion assay. Yorkshire piglets were weaned at 21 days of age and assigned to 2 groups of 8 on the basis of hemoglobin (Hb) concentration, litter, and sex. Iron depletion was achieved by simply withholding the iron injections normally given to newborn pigs. Repletion diets contained 780 g of iron fortified rice cereal per kg diet and new formulated to meet the nutrient requirements of piglets. The diets were identical except for the form of iron used to fortify the cereal (iron concentrations in the EI and FS diets were 118 and 127 mg/kg diet, respectively). The piglets were fed the repletion diets for 10 days. Means of initial/final Hb concentrations were 7.0/6.5 and 7.0/8.8 g/dL for the EI and FS groups, respectively. mean Hb iron gain (total Hb iron on day 11 minus total Hb iron on day 1) was significantly lower (P<0.001) in the group fed EI fortified cereal (20.62 versus 58.07 mg) Although the bioavailability of EI from commercial fortified infant cereals is low compared to FS, these products may supply a significant portion of the iron needs for many infants because of their high iron content. The piglet is a promising model for iron bioavailability studies.