A total of 10,202 individuals between 16 and 60 were investigated. In this manner, the material could be subdivided into a risk population consisting of the individuals who already were receiving anti-hypertensive treatment and those individuals in whom three blood-pressure measurements either revealed a systolic blood-pressure of more than or equal to 160 mm Hg or a diastolic pressure more than or equal to 95 mm Hg. Thereafter, the risk population was included in an intervention programme. The median blood-pressure for all persons investigated was 128 mm Hg. The median diastolic blood-pressure was 80 mm Hg. 1.9% of the individuals investigated were already receiving anti-hypertensive therapy and 2.5% of those examined had blood-pressures over the limits stated on all three measurements. The risk population thus consisted of 4,4% of all the persons investigated. Increasing systolic and diastolic blood-pressures were found with increasing age in both sexes. In the younger age-groups, however, the blood-pressures were higher for men than for women, whereas conditions were reversed in the older age-groups. No definite correlation was found between the blood-pressure level and the occupation or the composition of the household.