High blood pressure received more attention as common and potentially changeable risk factor, not only for card jo and cerebrovascu lar diseases, but also ¡n Alzheirner’s disease. The objective of the study was to evaluate the comorbidity between the Alzheirner dementia, vascular dementia, mixed dementia and high blood pressure and to establish the causal relationship between high blood pressure, as risk factor, and dementia. The study was conceived prospectively, with the comparative examination of 3 groups of patients: a group of patients with Alzheirner dementia (31 patients), a group of patients with mixed dementia (28 patients) and a group of patients with vascular dementia (22 patients).