A study has been made of hypertension and its associated vascular risk in 2319 male and 2412 female participants in the WHO Multinational Study of Vascular Disease in Diabetics. Rates of hypertension were higher in non insulin-dependent diabetics (NIDDs) compared with insulin-dependent diabetics (IDDs). On average, diastolic blood pressures were lower in IDDs than NIDDs. The frequency of isolated systolic hypertension varied between 2.5% and 5.6%. In a 6 to 7 year mortality follow-up, hypertension was significantly associated with an increased risk of circulatory death, even allowing for its association with proteinuria.