The neuroanatomic study of the median artery of the corpus callosum was performed by simple and careful dissection in 130 adult brains from northeasterner brazilians. The observation was realized with stereoscopic magnifying glass. The median artery of the corpus callosum was present in the 89,2% (116/ 130) of the cases. The artery exibited a gross caliber in 20% (26/130) of the specimens with the following patterns: a) in twelve brains (six on the right side and six on the left side) the median artery of the corpus callosum displaied a "predominant" unihemispheric pattern with regard to the distribution of their branches, and supplied the territory of the pericallosal artery of the correspondent side. The term "predominant" was used considering that in all the cases the artery supplied branches to the medial surfaces of both the cerebral hemispheres; b) in ten examples the median artery of the corpus callosum was a single trunk which then passed into the longitudinal cerebral fissure, and as an unpaired artery it supplied branches to the medial surfaces of both hemispheres; c) finally, in four cases, the median artery of the corpus callosum, at the level of the rostrum of the corpus callosum originated the two pericallosal arteries. With regard at filogenetic origin of the median artery of the corpus callosum it has been formulated the hypothesis that the artery possibly was originated by fusion of the callosal branches of the unpaired anterior cerebral artery of lower forms.