Essential hypertension, defined as a blood pressure equal to or above 140/90 mmHg, is a common (25% of the population), but complex disease the phenotype of which results from interactions between numerous genes and environmental factors. The role attributable to genetic factors amounts to some 25% among hypertensive families, but can reach 65% when monozygotic twins are compared. In the present state of our knowledge, there is no hope to obtain a genetic test of value for the diagnosis and prognosis of hypertension. An individualized environmental approach, applied early in life, is the only worhtwhile attitude. Nonetheless, in the presence of a subject with still normal blood pressure values, but with a family history of hypertension, the physician should firmly recommend an appropriate hygieno-dietetic lifestyle with a view to lower blood pressure, or retard the development of arterial hypertension