Little is known about the cognitive deficits associated with choreoacanthocytosis. This case report focuses on the neuropsychological deficits of a woman diagnosed with choreoacanthocytosis. The similarity between her cognitive deficits and those of patients with Huntington's disease is consistent with the neuropathology of the two disorders. The findings of this study suggest that careful neuropsychological assessment of patients with choreoacanthocytosis is warranted, since cognitive impairment may well be a clinical feature of the disorder.