We compared the degree of dementia in a group of 41 patients who, four years previously, had presented a first TIA with that of 31 healthy controls of similar age. For pathogenic diagnosis the Hachinski and Gustafson-Nilsson scales were applied, while mental state was evaluated by the Folstein, Blessed, GDS and CDR tests. We performed in all cases cerebral CT and several MR. The findings associated with dementia were the presence of multi-infarctions, leucoaraiosis or lacunes in the cerebral CT and the presentation of new ischemic episodes, sphincterian or gait disturbances and focal deficits. There were no differences with the control group in the cases only presenting one TIA. Polyglobulia was the only factor significantly associated with vascular dementia in these patients.