Transferrin is an important factor that is responsible for the transport of iron in the blood. It has got several polymorphisms, out of which there are three major isotypes and the polymorphism vary with different species. Transferrin is also distributed in various living cells and body fluids. Normal plasma concentration is necessary to be maintained and if it found less, then the susceptibility to various infections are more. Transferrin also has the ability to modulate differentiation and growth of cells. Apo-transferrin, a synthetic form of transferrin is highly recommended for the treatment of various clinical conditions. The present review helps in the overviewing of the structure of transferrin, polymorphism, functions of transferrin polymorphism and its clinical applications.