Severe hypercholesterolaemia include familial homozygous hypercholesterolaemia and certain heterozygous hypercholesterolaemias which become severe, due to spontaneous non-response to treatment or to iatrogenic side effects. Other causes include an associated overload in Lp(a) or uncontrolled atheromatous disease. Surgical treatment has been replaced by iterative LDL apheresis in these severe forms. Mean cholesterol and LDL cholesterol levels can be reduced by 41 to 63% and 49 to 68% respectively with LDL apheresis. In general, HDL cholesterol is protected in selective LDL apheresis. We observed similar decrease for apo B and LDL cholesterol levels. Fifty percent of the Lp(a) was removed in the 3 groups of patients studied.