"Masked hypertension" is defined as high blood pressure outside the medical setting (ambulatory or self-measurement at home) and normal BP in the medical setting Masked hypertension is frequent, particularly in patients receiving antihypertensive treatment. It is often associated with other cardiovascular risk factors. The cardiovascular prognosis in terms of target organ damage and complications is poorer than that of subjects considered normotensive by all measurement methods, and similar to that of subjects considered hypertensive by all measurement methods. Its pathophysiological mechanism is unknown. No controlled trials have yet been conducted to determine the possible benefits of treatment.