Children with familial hypercholesterolaemia are at high risk of developing coronary artery disease in early adulthood. The diagnosis should therefore be made in childhood. Population screening identifies a small number of children with major genetically determined disorders of lipid metabolism and a large number with polygenic hypercholesterolaemia of uncertain prognostic significance. Selective screening based on a family history of familial hypercholesterolaemia or premature coronary artery disease is an appropriate strategy for identifying most children with familial hypercholesterolaemia. A non-fasting total cholesterol measurement is a suitable screening test: if the concentration exceeds 5.5 mmol/l, a fasting measurement of total cholesterol, high-density lipoprotein cholesterol and triglyceride is required. The diagnosis in a child under 16 years should be based on finding a total cholesterol concentration greater than 6.7 mmol/l and a low-density lipoprotein cholesterol concentration above 4.0 mmol/l on at least two measurements taken more than one month apart. Children should not usually be screened before the age of two years, but the aim should be to diagnose heterozygous familial hypercholesterolaemia before the age of 10 years. Affected children should be referred for specialist care.