Hypertension is a risk factor for cardiovascular and renal organ damage. Environmental conditions affect the development of high blood pressure (BP), although genetic influences are also important. Current international guidelines recommend reducing dietary sodium to no more than 100 mmol (about 2.4 g sodium or approximately 6 g salt) per day to prevent BP rising; the current intake of sodium in industrialized countries is approximately double the recommended amount. Clinical trials (DASH and TOHP studies) have shown that dietary factors are fundamental in the prevention and control of BP. Low dietary sodium intake is particularly effective in preventing hypertension in subjects with an increased risk such as the overweight, borderline hypertensives or the elderly. A low-salt diet combined with anti-hypertensive therapies facilitates BP reduction independent of race. The hypotensive effect of calcium channel blockers is less dependent on salt intake than other drugs, such as ACE inhibitors or diuretics. Reduced sodium intake associated with other dietary changes (such as weight loss, and increasing potassium, calcium and magnesium intake) are important instruments for the prevention and therapy of hypertension.