Arterial hypertension is the most common chronic medical condition requiring office visits to physicians and is a major contributing factor to the development of myocardial infarction and stroke. Its importance as a cardiovascular risk factor is at least as significant in women as in men; however, the ever-growing literature on hypertension shows surprisingly little data concerning sex differences. Large clinical trials of antihypertensive treatment have not clearly demonstrated gender differences in blood pressure response and outcome, but the majority of patients in these trials were men. Even so, some evidence indicates that white women treated for hypertension obtain less benefit than men. The pathophysiology of hypertension in men and women is similar in many aspects, but important gender differences are now emerging. Studies designed to clarify these differences are required, as a better knowledge of the underlying mechanisms will allow for a more precise stratification of risk and a more accurate approach to both nonpharmacologic and pharmacologic treatment.