The purpose of this review is to examine the need for and appropriate level of Fe forti®cation of infant formula, and to assess any adverse effects of Fe forti®cation. The appropriate level of Fe forti®cation of infant formula has been established through studies of Fe absorption or erythrocyte incorporation of Fe, and through clinical trials of formulas with varying levels of Fe that were aimed at preventing the development of Fe de®ciency in participating infants. In addition, the effects of varying levels of Fe forti®cation on the absorption of other minerals and trace elements, and on the incidence of infection and immune function have been studied, as has the effect of adding bovine lactoferrin to formula. Studies