Two experiments were conducted to investigate the iron bioavailability of different sources and supply levels in piglets. In experiment 1, the influence of feeding an iron deficient basal diet or the basal diet supplemented with 28 ppm Fe either in form of Fe-chelate, crystalline Fe-glycinate, or Fe-sulphate on apparent iron digestibility and on blood parameters was determined. In experiment 2, a dose-response approach was used to determine the effects of supplementing an iron-deficient basal diet with 30, 60, or 90 ppm of Fe either in form of crystalline Fe-glycinate or Fe-sulphate on digestibility of Fe, growth and blood parameters. In experiment 1, comparison of iron sources revealed a tendency (0.05 < p < 0.1) for a higher Fe digestibility from Fe-glycinate (40.9%) compared with Fe-chelate (30.8%) or Fe-sulphate (30.7%). Fe-balance was higher (p < 0.05) for Fe-glycinate compared with Fe-sulphate but iron balance was similar for iron sulphate and iron chelate. Those results, however, were not reflected in data of blood parameters. In experiment 2, iron digestibility, blood parameters and performance were significantly (p < 0.05) influenced by iron supply. Effects of iron source on digestibility of iron were lower than observed in the first experiment.