BACKGROUND: It is now well established that atherosclerosis begins in childhood and evolves through adolescence and young adulthood, ultimately resulting in myocardial infarction and stroke in adults. MAIN TEST: Childhood is a critical phase during which atherosclerosis may begin to develop; in the presence of familial hypercholesterolemia, lifelong elevation of Low Density Lipoprotein cholesterol levels greatly accelerates atherosclerosis. These concepts, which have been largely developed from epidemiologic evidence, have not always been simple to implement in the paediatric clinical practice. The purpose of this article is to briefly review but also to highlight the rationale, the motivation and the methods in the process of identifying children and adolescents with familial hypercholesterolemia, an often hidden but very important genetic disease.