A systematic investigation of the structural, morphological, and electrochemical properties of anodes with a nominal composition of Ti/RuO2-Ta2O5 (Ru:Ta = 10:90; 30:70; 50:50 and 80:20 atom %) was performed. The oxide layer surface morphology, microstructure, and composition were investigated prior to and after accelerated life test through energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy. EDS analyses following total deactivation of the electrode showed a relatively large content of Ru in the coating. X-ray diffraction results showed the formation of a solid solution between RuO2 and Ta2O5 Cyclic voltammograms of this system were registered in acidic solutions (H2SO4 0.5 mol dm(-3)) and they presented a well-defined peak attributed to the Ru(III)/Ru(IV) solid-state redox transition. The electrocatalytic activity shows a strong dependence on the RuO2 content in the film. The stability of the electrodes toward oxygen evolution reaction was evaluated at 0.5 mol dm(-3) H2SO4, using a current density of 750 mA cm(-2) and a temperature of 80degreesC. A direct dependence between the electrode lifetime (LT) and RuO2 present in the coating was observed. Upon changing TiO2 for TA(2)O(5) (Ru = 50 atom %) a considerable improvement (average of 54%) in the LT values of these oxides was obtained. This result is a good indication that the Ru/Ta system might be a promising coating to operate under severe conditions. (C) 2004 The Electrochemical Society.