Raised blood pressure is one of the most important underlying risk factors for morbidity and mortality in the world today, ranking alongside tobacco in estimates of the worldwide attributable burden of mortality. It is a major risk factor for coronary heart disease and the major risk factor for stroke. Taken together, the cardiovascular diseases are estimated to account for some 28% of all deaths in the world. Already many more of such deaths are occurring in the developing than the developed world, and this burden of disease is set to worsen as a result of demographic changes in the poorer countries, together with adoption of Western lifestyle. The development of unfavourable blood pressure patterns in populations is a key factor underlying this worldwide epidemic. Both primary prevention (for example through improved diet) and secondary prevention (through drug treatment and non-pharmacologic approaches) are needed.