Transferrin (TF) is a secreted protein which belongs to the transferrin family. It is expressed by the liver and secreted in plasma. TF has a molecular weight of around 80 KDa and contains two specific high-affinity Fe (III) binding sites. TFs are iron-binding blood plasma glycoproteins that control the level of free iron in biological fluids. The main role is to deliver iron from absorption centers in the duodenum and white blood cell macrophages to all tissues. TF is associated with the innate immune system. The level of TF decreases in inflammation. An increased plasma TF level is often seen in patients suffering from iron deficiency anemia. A decreased plasma transferrin can occur in iron overload diseases and protein malnutrition. Most recently, TF and its receptor have been shown to diminish tumour cells when the receptor is used to attract antibodies. TF is an acute phase protein and is therefore seen to decrease in inflammation, cancers and certain diseases.