Alzheimer's disease is a progressive brain disorder that gradually destroys a patient's memory function and ability to carry out daily activities. According to the prevailing amyloid cascade hypothesis, Alzheimer's disease is initiated by amyloid beta-peptide accumulation leading to neuronal toxicity. The neurofibrillary tangle deriving from hyperphosphorylated tau and synapse loss are also key features for Alzheimer's disease. Recent studies revealed a significant co-morbidity of Alzheimer's disease and cerebrovascular disease suggesting that cerebrovascular dysregulation is an important feature of Alzheimer's disease. This mini-review will discuss the hypothesis that a dysfunction of the vascular system may result in damage of the neurovascular unit, initiating a cascade of events. An overlap with other forms of cognitive impairment, such as mild cognitive impairment, or vascular dementia will be discussed.