The development of hypertension care over the 10-year period 1972-1982 in North Karelia and a reference area was assessed using three separate random samples of the population aged 30-59 years. The results show a clear improvement in the blood pressure levels of the population and in the hypertension care in North Karelia between 1972 and 1977 when the activities of the hypertension program of the North Karelia Project were gradually implemented. Awareness of elevated blood pressure increased from 39% to 71% among men and from 60% to 87% among women. The proportion of men under antihypertensive drug treatment increased from 4% to 10% and that of women increased from 10% to 15%. After 1977, the hypertension care was maintained but no further improvements were observed in general blood pressure levels. An improvement in hypertension care started in the reference area later than in North Karelia. In spite of favorable changes, the blood pressure level of the population was still high in 1982, the mean casual value among men being 145/87 mmHg and that among women being 141/84 mmHg. It is obvious that further progress in hypertension care is needed.