In Finnmark county in Norway, 12 329 males and females aged 20-49 years participated in two screening examinations with an interval of 3 years. The primary health service attempted, without receiving any extra resources, to reduce the risk of cardiovascular disease by means of a personal intervention programme among high-risk individuals and a health education programme directed at all residents in the county. During these 3 years the serum total-cholesterol (cross-sectionally) level decreased on average by about 0.3 mmol/l due to: firstly, a decrease among persons recommended a follow-up examination and secondly a decrease among household members of persons followed-up. The effect of a recommendation to attend a follow-up examination because of high blood pressure was doubtful. Cigarette consumption (cross-sectionally) decreased 12% for males and 4% for females. The joint decrease (improvement) in risk factors indicates a possible health benefit of about 20%, calculated in terms of myocardial infarction over 10 years.