To assess the causes of high serum ferritin (over 1000 nanogram/ml) the records were reviewed of 145 samples of blood with ferritin levels over 1000 ng/ml taken in 2004 at Hamad Medical Corporation. The most common causes of hyperferritinemia in Qatar were found to be: end-stage renal failure, thalassemia major and sickle cell disease. Introduction: Ferritin is a globular protein complex consisting of 24 protein subunits and is the main intracellular iron storage protein in both prokaryotes and eukaryotes, keeping the iron in a soluble and non-toxic form. Ferritin is found principally in the intestinal mucosa, spleen, and liver, functioning as the primary form of iron storage in the body. (1) Ferritin that is not combined with iron is called apoferritin. Ferritin behaves as an acute phase reactant in various disease states such as rheumatoid arthritis, both adult and juvenile Still's disease, infections, and systemic lupus erythematosus. (2) Ferritin levels are high in patients with hemochromatosis, other liver diseases, alcoholism, renal diseases, malignancies, in patients who have had multiple transfusions , infection, and Still's disease. (3) We studied the files of all patients at our hospital who had high ferritin levels above 1000ng/ml during the year 2004.