Cardiovascular disease is the main cause of death in virtually all industrialised countries. The limited information available from developing countries suggests that a similar epidemic is inevitable if current trends go unchecked. Treatment of patients with clinical manifestations is an important element in overall management but on its own is an insufficient and incomplete response. Sudden death is often the first manifestation of cardiovascular disease and, even when treatment of disease is applicable and effective, it is usually palliative rather than curative. Thus treatment and prevention directed at the underlying risk factors, including high blood pressure, constitute a complementary and more fundamental approach to reducing the burden of illness. Epidemiological studies provide the scientific foundation for such an approach by identifying the distribution and determinants of high blood pressure in the general population, by establishing the role of high blood pressure as a risk factor for cardiorenal complications, and by quantifying the potential value of treating and preventing high blood pressure in the general population.