To improve the iron status of infants an effort was made to increase the iron content of complementary foods by adding 12.5 mg of elemental iron to the meal in the form of micro-encapsulated ferrous fumarate coated with a lipid. The contents of the packet were sprinkled directly on to infant foods. Relative absorption of iron from this supplement was determined in a prospective randomized study with 39 infants (mean age 33.6 +/- 5.2 weeks) with initial hemoglobin values greater than 100 g/L. They were fed two complementary foods (rice-based and wheat-based) in which the supplement labeled with stable isotopes of iron 57Fe and 58Fe was incorporated. The erythrocyte iron incorporation was measured in the blood by inductively coupled plasma mass spectrophotometry. The incorporation of iron was significantly higher 11.9% p < .001 and 13.3% p < .001 and no difference was observed with the type of cereal in complementary foods. The use of ferrous fumarate sprinkles has proved to be efficacious in increasing the available iron intake of the infants.