As an advanced oxidation treatment, Fe(III)/H2O2/solar UV process was applied to an azo dye, Reactive Blue 19 (RB19), a widely used textile dyestuffs in the Turkish textile industry. A solar photocatalytic reactor was used for the advanced oxidation. Box-Wilson experimental design method was employed to optimize the wastewater flowrate, oxidant and catalyst concentrations as significant factors for maximum decolorization and organic matter removal. Color and organic matter removals were monitored throughout the operation period. Complete decolorization (E = 100%) was obtained for the strong dye solution with 50 mg/L dyestuff concentration with the addition of 2677 mg/L H2O2 and 0.5 mM Fe(III) at 10 L/h flowrate after 8 h of exposure to the solar irradiation. The maximum reduction in the total organic carbon (TOC) concentration was 90% under the same operating conditions. (C) 2010 Elsevier B.V. All rights reserved.