The aim of this study was to investigate the effects of different doses of iron on haematological status of breastfed infants. One hundred and thirteen infants were randomized into four groups at 5 months of age. Iron supplementation was given at doses of 1 mg/kg/day, 2 mg/kg/day, and 2 mg/kg/every other day in the first three study groups, respectively, and the last group received placebo. The hematological values, except hemoglobin, were higher in the group supplemented with iron at a dose of 2 mg/kg/day, and ferritin values were statistically higher in the group supplemented with iron at a dose of 2 mg/kg/every other day than in the group supplemented with iron at a dose of 1 mg/kg/day. We suggest that intermittent iron supplementation is more effective than a daily regimen in equal dosages.