In 15 normotensive subjects, 17 newly diagnosed, untreated hypertensive patients, and 22 effectively treated hypertensive patients, a battery of neuropsychological tests was given. All subjects were neurologically asymptomatic. The neuropsychological battery included tests evaluating global cognitive functions (Card Sorting Test, Wechsler Memory Scale, Progressive Matrices 1938), as well as specific cognitive functions (Benton Test, subtests of the Wechsler-Bellevue Scale). Normotensive controls obtained better scores in all the tests. Statistical analysis of th scores suggests that hypertension is highly correlated with impairment of memory, logical reasoning, visuospatial organization, and attention. Therapy seems to impair attention, while the duration of disease seems to influence visuospatial performances.