A community-based programme to improve awareness and control of hypertension was launched in 1972 in North Karelia. It was incorporated in the existing health-services system. An assessment five years later showed that, compared with a reference area not included in the programme, awareness of hypertension had improved, the prevalence of hypertension had dropped, levels of blood-pressure were lower by age-group, and the number of people on antihypertensive treatment had increased.