Hypertension is a major risk factor for cerebral and coronary disease and its early detection is very important for the family physician. We checked the implications of a hypertension survey in the community (from the age of 10 years) on the attitude of the primary care team. We found that although the medical team was aware of the significance of early detection and treatment of hypertension, according to the "law of halves" half the hypertensives were in treatment and of them half had normal blood pressure. This fact is probably not related to the quality of medical care. High risk groups identified were hypertensive patients who smoked, Jewish men of western origin, and Jewish women of Asian-African origin (who had a high rate of strokes). These groups were targeted for active intervention by the primary care team. This survey is part of planned community-intervention by the primary care team in the field of hypertension.