Photoelectrochemical (PEC) degradation of Procion Red MX-5B was investigated in aqueous NaCl solutions. PEC degradation efficiencies showed strong dependence on the concentrations of aqueous NaCl solutions and applied potentials. 95% decolorization of the dye could be achieved in 10 minutes at applied potential of 8 V in 0.3 M NaCl solution, while the efficiency was only 35% by photocatalytic oxidation. Electrodegradation can be as powerful as PEC degradation upon dye decolorization when the potential exceeds 5 volts. However, it can not mineralize dye degradation intermediates by itself alone. PEC degradation performed very high TOC removal capacity and nearly 80% of total organic carbon was removed in the first hour of reaction, compared with 50% removal in PCO process during the same period.