This article reviews experimental and clinical evidence of whether primary hypertension (HTN) later in life is influenced by events early in life. The experimental evidence is drawn from studies in inbred strains of HTN-prone rats; the clinical evidence is drawn from studies in children and adults of the influence of genetics, nutrition, and stress on adult blood pressure (BP). Adult BP in HTN-prone rats is significantly influenced in the preweaning period by salt intake and genetic factors regulating extracellular fluid volume, and by maternal-infant interactions. BPs of children track with BPs of their parents. Children of parents with primary HTN are insulin resistant and have lower average cation flux values across cell membranes as do their parents; children and their parents with secondary HTN do not. Children with low birth weight have a higher prevalence of HTN as adults than better-nourished peers. Salt intake in children affects BP response to stress. Average salt consumption among different cultures correlates with the prevalence of HTN in those cultures. Varying salt intake of infants and children has little influence on BP later in childhood. The evidence suggests simple measures that might lower the risk for HTN in HTN-prone children in general. However, at present we lack reliable means for identifying children at risk for HTN specific means to lower that risk.