This paper presents a review of the genetic transmission of normal blood pressure and of essential hypertension. Familial aggregation of normal blood pressure has been reported in adults, in children and even in newborns. Blood pressure aggregation phenomenon, however, is the result of both a genetic component and shared environmental factors. More specific for each etiological factor were the studies of blood pressure aggregation in twins and in adopted children. Attention was focused on the Montreal Adoption Study. In essential hypertension, a Japanese study is reviewed showing the occurrence of hypertension in the offspring of hypertensive parents. The heterogeneity of essential hypertension is underlined and two of the multiple etiological factors are particularly considered for their genetic component: the response to salt intake and erythrocyte cation fluxes. The conclusion from the literature reviewed is that essential hypertension is a polygenic disease transmitted by polygenic systems.