Two forms of verbal fluency test, phonological (FF) and semantic (FS) sets, have been administered to four groups of demented patients: 11 with Alzheimer-type dementia (DAT), 13 with multi-infarct dementia (MID), 8 with Parkinson-Dementia (P-D) and 11 with adult chronic hydrocephalus (ICA). Patients were matched for age, educational level and neuropsychological impairment pattern. Further, ten neurologically healty subjects were selected as control group. Control subjects result to be different from all other groups in both FF and FS; moreover, FF test results to be more impaired in ICA than in DAT. Furthermore, FF is more impaired than FS in P-D and ICA patients. On the basis of our results, verbal fluency tests might represent an useful instrument to differentiate demented subjects from non-demented ones and within demented groups to characterize the different neuropsychological pattern of the cortical and subcortical type of cognitive deterioration.