Familial hypercholesterolemia is a disorder of lipoprotein metabolism characterized by elevated cholesterol, low-density lipoprotein cholesterol, xanthomas and early onset atherosclerosis. Tendinitis and arthritis have been reported in patients with familial hypercholesterolemia. A report is presented of a 9-year-old girl with an acute arthritic attack who was diagnosed as homozygote familial hypercholesterolemia with hypercholesterolemic arthritis.