Continual nitric oxide (NO) synthesis is important in the regulation of vascular tone and thus blood pressure. Whereas classically NO is provided by the enzymatic oxidation of l-arginine via endothelial NO synthase, it is now clear that NO can also be generated in mammals from the reduction of nitrite and nitrate. Thus inorganic nitrate derived either from NO oxidation or from dietary sources may be an important storage form of reactive nitrogen oxides which can be reduced back to nitrite and NO when physiologically required or in pathological conditions. The very short half-life of NO and the ready availability of stored nitrite and nitrate make for a very sensitive and responsive blood pressure control system. This review will examine processes by which these storage forms are produced and how augmentation of dietary nitrate intake may have a beneficial effect on blood pressure and other vascular function in humans.