The aim of the present work is to prove that the complexation of the metals Pb, Cd, Mo, Cu, Zn and Cr with chitosan takes place. In order to show it, voltammetric measurements have proved useful [12]. Depending on the different electrochemical behaviour on mercury electrode of the studied metals and the nature of the resulting complexes, diverse approaches have been used. The effect of the molecular weight and concentration of the polymer on the binding of the metals has also been studied.