Treatment of textile wastewaters containing dyes has not been very successful by conventional methods such as biological treatment. In order to overcome this problem, ozonation based on the oxidation of organic pollutants has been studied by researchers. Catalytic ozonation and advanced oxidation processes (ACPs) are used in order to increase the efficiency of sole ozonation further. In this work, catalytic ozonation in the presence of copper sulfide (CuS) powder as a catalyst was investigated in the treatment of aqueous single dye solutions, namely solutions of Acid Red-151 (AR-151), Remazol Brilliant Blue-R (RBBR) and Reactive Black-5 (RB-5). In the catalytic ozonation experiments, the effects of important ozonation parameters such as solution pH, ozone and catalyst dosages and the initial concentration of each dye on reaction kinetics and mechanism were studied.