The service life of SnO2-Sb2O5 coated anodes prepared by the spray pyrolysis technique using Ti or Ti/IrO2 substrate, was studied under galvanostatic conditions (100 mA cm(-2) in 1 M H2SO4 at 25 degrees C, The results showed that the presence of an IrO2 interlayer between the Ti substrate and the SnO2-Sb2O5 coating (Ti/IrO2/SnO2-Sb2O5 anode) strongly increases the service life of the anode. This beneficial action of the IrO2 interlayer was attributed to its high anodic stability and its isomorphous structure with TiO2 and SnO2. Cyclic voltammetry anti steady-state polarization curves showed that the electrochemical behaviour of the Ti/IrO2/SnO2-Sb2O5 electrode lies between the behaviour of the Ti/IrO2 and the Ti/SnO2-Sb2O5 electrodes due to incorporation of IrO2 in the SnO2-Sb2O5 coating during its preparation.