The TR is a vital surface component which has been demonstrated to be involved in processes critical for cell metabolism and growth. This review has attempted to briefly touch on the more well understood aspects of study of the TR. These aspects include the biochemical characterization of the TR and the functional studies concerning the central role of the TR in binding transferrin for the purpose of internalization and accumulation of intracellular iron. Other less well-understood and controversial aspects surrounding our present knowledge of the TR have been highlighted and discussed. These include: the nature of the biochemical signal involved in triggering receptor endocytosis; the role for the transferrin-TR interaction or the TR alone in regulation of cellular growth processes; and the possible clinical role(s) for the TR in anti-tumor therapy.