Advanced oxidation process based on dielectric barrier discharge at the gas water interface was used for the oxidative decomposition of dye contaminated wastewater. The advantage of plasma treatment over conventional physical methods of pollutants removal is the mineralization of pollutant, whereas in physical methods, pollutants may be transferred from one form to another. The effect of various parameters like applied voltage, gas flow rate, concentrations of dye, addition of Na2SO4 and Fe2+, formation of H2O2 and change in pH were investigated for methylene blue degradation. The high degradation yield up to 67 g/kW h was achieved during the present study. Hydrogen peroxide, a powerful oxidant formed during the reaction was confirmed and addition of Fe+2 improved the performance, possibly due to Fenton type reactions. It has been observed that dye degradation followed first order kinetics. (C) 2012 Elsevier B.V. All rights reserved.