In an undivided cell, the degradation of methyl red via indirect single and paired electrolysis in the presence of bromide and hydrogen peroxide redox mediators was explored. The factors that affected the degradation rate of methyl red are discussed, including the concentration of methyl red, the kind of electrolyte, the concentration of sodium bromide, the anodic current density, the material of electrode, the cathodic current density and the flow rate of oxygen at the catholyte. The results revealed that the major factors were the concentration of methyl red, the kind of electrolyte and the current density, and that the minor factors were the concentration of NaBr, the type of electrolysis, the flow rate of oxygen and the cathode material. The optimum operating conditions of this system were found to be 40 ppm methyl red, 2.0 M NaBr, 3.38 mA.cm(-2) anode current density, 2.96 mA.cm(-2) cathode current density, 50 ml.min(-1) O-2, and graphite used in working and counter electrodes.