Objectives: Although dementia is one of the most relevant symptoms of the idiopathic Normal-Pressure Hydrocephalus (iNPH) syndrome, some doubts remain about the nature of cognitive deficits in this disease. We aimed to determine the neuropsychological profile in iNPH and its relation with ventricular size, white matter vascular lesions (WML) and gait dysfunction. Methods: Seventeen iNPH patients and a control group (n =14) were assessed with a battery of neuropsychological tests and a timed walk test. We calculated measures of frontal horn, occipital horn and third ventricle sizes and assessed white matter lesion (WML) load with a validated visual scale. Results: Patients differed significantly from controls in all cognitive tests, but did worse on the Rey Complex Figure test. We found no significant correlations between cognitive and imaging results in iNPH. Cognitive function was related to gait in controls, but not in iNPH patients. Conclusions: Patients presented widespread cognitive dysfunction with a predominance of visuo-spatial deficits. Dissociation between gait and cognitive dysfunction in iNPH patients suggests the existence of different pathophysiological mechanisms. (C) 2014 Elsevier B.V. All rights reserved.