The distribution of cholesterol values was established in a group of 2,000 Prague children aged 11-12 years. Of these, 100 children with cholesterol values exceeding the 95th percentile (HYPER), and 100 children with values between the 5th and the 10th percentiles (HYPO) were selected for follow-up. In addition to a thorough clinical and laboratory examination in children and parents, three-day food consumption was registered in children. Even though differing significantly from those assigned to the HYPO group in lipid spectrum parameters, HYPER group children did not show any abnormalities in carbohydrate metabolism or increased incidence of obesity. There is no significant difference in the energy values of food consumed by HYPER and HYPO children. Although a significantly higher proportion (in per cent) of total lipids and animal fat consumption was found in HYPER boys (p less than 0.05), the proportions (in per cent) of fatty acids, and the unsaturated/saturated fatty acid ratio in HYPER and HYPO children did no differ significantly. Parents of HYPER children showed significantly higher mean values of cholesterol, apolipoprotein B, LDL cholesterol and more unfavourable atherogenic index values. Hypercholesterolaemia aggregation in both parents was likewise significantly higher in children assigned to the HYPER group.