The morphological variability, diameter, and length of the anterior communicating artery (ACoA) are important factors in clinical and surgical decisions. This artery presents branches that supply the optic nerves and chiasm, the lamina terminalis, the hypothalamus, and the subcallosal region. The ACoA has the most frequent incidence of saccular aneurysms in the anterior portion of the circle of Willis. Lesions to the ACoA's branches may be related to neuropsychological sequelae such as amnesia, confabulation and personality changes, besides other basal ganglia syndromes. In this paper, anatomical studies of the ACoA and its branches are reviewed and the results of an anatomical study carried out in our laboratory presented.