In the recent years, classical vascular risk factors have been suggested to play a role also in the development of degenerative dementia. Arterial hypertension has been implicated in the pathogenesis of dementia but no conclusive results have been produced yet; more recently, blood pressure variability (BPV) has been suggested as a more important risk factor for both silent brain vascular lesions and the development of dementia. Blood pressure variability is defined as the variation in blood pressure over time, measured on different time spans and in different ways. We reviewed current scientific literature about the role of BPV in the pathogenesis of dementia, and about the association of abnormal BPV patterns and different forms of dementia. We also suggested some hypothetical pathogenic mechanisms.