Tin dioxide electrodes are used as anodes for the electrochemical destruction of organic pollutants in wastewater : The lifetime of such electrodes is limited because of corrosion phenomena which are shown to take place under anodic polarization. These corrosion processes are studied by quartz microbalance experiments, impedance measurements, transmission electron microscopy and scanning electron microscopy observations, carried out on sprayed SnO2 layers. Localized corrosion phenomena are observed and related to the reaction of radical species with the oxide surface. The extent and the morphology of the attack is shown to depend on the doping (F, Sb) of the SnO2 electrodes, the solution pH, and the concentration of chloride ions. It is also shown that because of corrosion the conduction band energy level is shifted toward much more positive potentials, allowing the SnO2 electrode to be activated for oxygen evolution.