Acid Orange 7 dye was decompd. by electrochem. and photoelectrochem. oxidn. on CeO2-modified Ti/TiO2-RuO2 electrodes under UV irradn. The highest dye conversion degree was achieved on Ti/70%TiO2-30%RuO2 electrode without CeO2 in the oxide film when the wavelength 254 nm was applied. When the radiation in WS region was applied, the highest conversion was achieved on the Ti/94%TiO2-3%RuO2-3%CeO2 electrode.