A large multicentre study of coronary heart disease risk factors and their determinants in children and adolescents was planned in the late 1970s. The main cross-sectional study with 3,596 subjects was made in 1980, and two follow-up studies have been carried out, in 1983 and 1986, respectively. In addition, a study with 630 newborns was carried out in 1981, and a series of children aged 1 to 36 months was collected in 1981-1982. Cord blood, serum cholesterol was about 1.5 mmol/l, which is no different from the level found in other studies. The diet of mothers had no effect on the cholesterol values of the newborns. The cholesterol level of infants and small children was correlated with the amount and quality of fat eaten. The dietary habits of the family were correlated with the family's standard of education, which calls for intervention measures already in early childhood. Serum cholesterol levels have decreased in Finnish children during the 1980s by about 1% per year, which should be reflected in coronary heart disease morbidity and mortality in the future.