The biological and physiological activities of milk proteins are partially attributed to several peptides encrypted in the protein molecules. These peptides can be liberated by enzymatic digestion in vitro and in vivo. Among the biologically active molecules, phosphorylated peptides (caseinophosphopeptides, CPP) are known to exert an effect on calcium metabolism but also on other minerals. While the existing discrepancy on the potential role of CPP on calcium availability has not been clarified, the results of our previous studies showed that a purified phosphopeptide (beta(1-25)) exhibits a positive effect on iron bioavailability in vivo. Here we report the main results on the efficiency of beta(1-25) in the absorption and availability of iron as well as on the mechanism involved.