This paper presents voltammetric and electrochemical impedance studies of the anodic oxidation of chalcopyrite in the presence of highly concentrated sodium isopropyl xanthate solutions. The voltammetric response of the system displays a passivating effect on the chalcopyrite surface with the addition of xanthate due to its adsorption, which also impedes the transportation of oxidized species, ie, Fe 2+ and Cu 2+ from the mineral matrix outwards the interface. The impedance spectra obtained near the polarization potential, at which the passivating effect is observed in the voltammograms shows a pseudocapacitive effect in the system, which is associated to the adsorption of xanthate and blocking the interface. The impedance spectra obtained show three time constants associated with the oxidation reactions of chalcopyrite and xanthate and the formation of covellite and cuprous xanthate on the mineral surface, the EIS results are according to the voltammetric response obtained for the system.