Familial hypercholesterolemia (FH) is an inherited autosomal dominant disease caused by mutations of LDLR gene. The disease is in fewer cases caused by mutations of genes APOB or PCSK9. Mutations can be manifested by insufficient receptor synthesis or functionality disorders. This results in the insufficient low-density lipoprotein (LDL) breakdown and the increase of its plasma levels which leads to early and rapid atherogenesis. The incidence of FH in heterozygotes amounts to 1:200 to 1:250, which makes it the most common hereditary disease. More severe, homozygous form of disease is much rarer, with its incidence being 1:1 000 000. The onset of symptoms is proportional to LDL blood concentrations. In heterozygotes, the symptoms most often appear in early adulthood in the form of coronary disease, while cholesterol deposits around tendons (tendon xanthomas), above joints (tuberous xanthomas), and in the eyelids (xanthelasma) rarely occur before adulthood. In homozygotes, xanthomas appear in the first years of life, while the cardiovascular disease is usually manifested before the tenth year of life. It is very important to recognize FH in childhood considering that disease development starts from birth, and blood vessel changes can be seen even in children. Due to the high incidence, FH represents an important public health issue. However, the complications of the disease can be prevented by the identification of affected families, cascade screening, and enforcement of preventive measures already at a young age. The disease in children is most commonly established by chance, after identifying high LDL blood concentrations or after a family member gets diagnosed, or, in rare cases, after the development of early clinical manifestations of atherosclerosis. The diagnosis can be confirmed phenotypically or with LDLR gene analysis. If the test is negative, the analysis should be extended to genes for apoB and PCSK9. The basis of treatment is maintaining LDL concentrations below 3,5 mmol/L. That is primarily achieved by diet and regular physical activity, with smoking and obesity prevention. Usually, around the eighth year of life treatment with statins begins. Since recently ezetimibe is used which inhibits intestinal cholesterol absorption. In homozygotes, lipoprotein apheresis is implemented early, and in the most severe cases liver transplantation may be performed. Beside the treatment, it is important that patients have regular follow-ups that include cardiovascular disease progression assessment.