Decolorization of C.I. Reactive Red 2 (RR2) and C.I. Acid Orange 6 (AO6) using a catalytic ozonation system was evaluated. The decolorization rates for RR2 and AO6 were accelerated by at least 30% by adding MnO2 to the O-3 system; additionally, the decolorization rate increased as the MnO2 dosage and ozone power consumption increased. Enhanced MnO2 catalytic ozonation was more apparent for AO6 than for RR2.