Titanium anodes were sol-gel coated with RuO2+SnO+TiO2 containing various amounts of SnO2 by brushing, sintering and annealing. The effect of SnO2 on the microstructure; morphology and particle size of the RuO2+TiO2+SnO2/Ti coatings was examined by XRD, DTA and TEM. It was concluded that the crystal size of the coatings, which was on the scale of nanometers, was sharply reduced with increasing SnO2 content. At same time, it was shown that the coatings, which consisted mainly of a solid solution- (Ru,Sn,Ti)O2 , would remain stable and monophase during increases of the SnO2 content and the annealing temperature. The morphology of the RuO2+TiO2+SnO2 crystals in the coating was equiaxial, due largely to the presence of the SnO2.