Treatment of textile wastewater with the Advanced Oxidation Process (AOP) is based on using the H₂O₂/UV system. The optimum condition for treatment of an effluent sample was determined by ex- perimenting on a synthetic dye solution prepared using the blue sulfur dye. Different parameters that affect the reaction rate were tested (UV intensity of 18, 36 and 54 W, initial dye concentration of 70, 80, 90 and 100 ppm, pH 3, original pH of the solution equal to 7.29 and 10 as well as the catalyst dose). Absorbance was measured to determine the decolorization efficiency and then the total organic carbon was measured for the reactions at optimal conditions to assure that decolorization is accompa- nied by degradation.