The mammalian erythrocyte is a very suitable model for the study of aging at the cellular and molecular level. It is not only a matter of apparent simplicity in terms of biochemistry, biophysics and physiology but more likely this cell offers a great possibility for elucidating some basic problems in the process of aging. In fact, nowadays, it is possible to follow individual cells all along their life span in circulation, it is possible to obtain these cells when young, middle aged or old and it is possible to obtain cells from individuals of defined ages and transfuse them into compatible...