Ferritin is the main iron storage protein that plays an important role in iron homeostasis and is concerned with many physiological functions and pathologic disorders. Clinically, ferritin is mainly used as a biomarker for total body iron stores. Serum ferritin has a critical function in both iron deficiency and overload that related to the diagnosis and treatment. High levels of both serum and tissue ferritin are related to the coronary artery disorder, cancer, and bad results after stem cell transplantation. Less commonly, ferritin is related to other human diseases like the neurodegenerative complaints, sideroblastic anemias, and hemophagocytic disorder. Moreover, up to date research explains a novel function of ferritin that not related to the iron storage.