Epidemiological and clinico-pathological data indicate that there is considerable overlap between Cerebrovascular disease (CVD) and Alzheimer’s disease (AD) and suggest that there are additive or synergistic effects of both pathologies on cognitive decline. The most frequent vascular pathologies in the aging brain and in AD are cerebral amyloid angiopathy and small vessel disease. Up to 84% of aged subjects show morphological substrates of CVD in addition to AD pathology. Although the effects of CVD on the development and progression of dementia are unclear, it has been well confirmed that CVD contributes to the neurodegeneration of AD. Further study of the relationship between CVD and AD will allow us to fully understand the mechanism of the development and progression of dementia and lead to the discovery of other novel therapeutic targets for AD.