Stroke is one of the most-frequent causes of death and the first cause of disability worldwide. Different mechanisms are related to the pathogenesis of stroke, involving multiple biological systems, which are often inter-connected. Besides age, hypertension is the most important risk factor for stroke and may also predispose to the development of more subtle cerebral damage based on arteriolar narrowing or pathological microvascular changes. Age and high blood pressure are responsible for silent structural and functional cerebral changes leading to white matter lesions and cognitive impairment. The clinical significance and pathological substrate of white matter lesions are not fully understood. Hypertensive patients have more white matter lesions, which are an important prognostic factor for the development of stroke, cognitive impairment, dementia and death, than normotensive people. Over the past 10 years, strong evidence has emerged that cerebral white matter lesions in hypertensive patients should be considered a silent early marker of brain damage. The mechanisms that would explain all these relationships remain to be elucidated, but available data suggest that arteriosclerosis of the penetrating brain vessels is the main factor in the pathogenesis of ischemic white matter lesions.