This study tested the association between cognitive functions, cerebrovascular damage, and cerebrovascular reactivity in 71 essential young hypertensives (age matched) and 22 normotensives (age matched). They underwent ambulatory blood pressure monitoring, neurocognitive tests, cerebral magnetic resonance, and transcranial Doppler. Twenty-three percent of patients showed more than 10 white matter lesions and 8% showed none. No control subjects showed more than 10 white matter lesions and 90% of normal controls showed no lesions. Patients with more than 10 white matter alterations had longer hypertensive story and showed significant lower nocturnal blood pressure fall. Pulsatility index was correlated with the number of white matter lesions.