A photoelectrochemical process in the degradation of an azodye (Acid Orange II) on a Pt/TiO2 film electrode was investigated. By using the glass device and the voltage stabilized source of direct current, decolorization ratios higher than 78% were observed during aperiod of 5 h. Comparing this value with the sum of the decolorization ratios obtained by a sole application of electrochemical (lower than 3%) and photochemical (about 23%) procedures, a significant synergic effect between both processes was observed. The effects of adscititious voltage and pH value on the decolorization ratios were obvious while the effect of the amount of aeration was minor.