Hypertension is one of the major risk factors for cardiovascular disease, the prevention of which is acknowledged to be critically important. Human beings are the only animal species which consume large quantities of salt, and their consumption has increased with the advancement of civilization. Many observational and interventional epidemiologic studies have demonstrated that a high intake of salt results in elevation of blood pressure, and that a salt-reduced diet induces blood pressure reduction in patients with hypertension as well as in individuals with normal blood pressure. Reduced salt intake, blood pressure reduction, and a remarkable decrease in mortality due to stroke in Japan are important examples of this effect. A decrease in the mean blood pressure in an entire population can contribute significantly to decreased incidence of cardiovascular diseases. A population-based strategy for preventing hypertension, including a salt-reduced diet, is therefore desirable. Proposed measures include public health education by the mass media, reduced salt content in processed foods, salt reduction in foods served by schools or organizations and at restaurants, and labeling of salt content. Further studies are needed of population-wide salt reduction methods, and the effectiveness of such methods.