The anterior choroidal artery syndrome is extremely rare. When complete, it includes hemiplegia, hemianaesthesia and homonymous lateral hemianopsia. The diagnosis is provided by computerized tomography which shows a low-density area located in the posterior part of the posterior limb of the internal capsule, sparing the thalamus medially but involving the tip of the pallidum externally and corresponding to the territory of the anterior choroidal artery. Incomplete forms of the syndrome have been described. The syndrome may also be associated with neuropsychological disorders, including left neglect syndrome in right-sided lesions and disorders of speech in left-sided lesions. The anatomico-clinical correlations are discussed.