EUROSTROKE is a collaborative study among ten European research centres to investigate (1) the variation in incidence of fatal and non-fatal ischaemic and haemorrhagic stroke among populations in different European countries; (2) whether the observed differences in stroke incidence across countries can be explained by differences in prevalence of established cardiovascular risk factors; (3) the relative importance of selected dietary factors (potassium intake, smoking, alcohol consumption), haemostatic disturbances (fibrinogen) and co-morbidity (rheumatic heart disease, atrial fibrillation) compared to established risk factors as determinants of the occurrence of ischaemic and haemorrhagic stroke. The EUROSTROKE database is drawn from ten European population-based prospective follow-up studies (cohorts) and is designed as a case-control study nested within these ten ongoing studies.