In this study, sex and age related differences of the human corpus callosum were studied by magnetic resonance imaging (MRI). 301 normal individuals (154 females and 147 males) without apparent neuropathology were examined on T1-weighted midsagittal brain sections. Maximum length and the corpus callosum index [(maximum length of the corpus callosum/hemisphere length at the same horizontal plane) x 100] did not show a signiticant difference between the sexes in age-matched subgroups (p>0.05). The corpus callosum maximum length decreased with chronological age in females but not in males, while the corpus callosum index did not change. Corpus callosum was divided into three segments using the straight-Iine method and area of the three segments and total callosal area were measured. No sex differences could be found for these parameters (p>0.1 ).