In this study, decolorization of the synthetic wastewater containing Reactive Yellow 15 (RY15) by means of the heterogeneous Fenton process was investigated. Primarily, the Fe/CuO catalyst was prepared by co-precipitation method and characterized by BET and SEM-EDX analyses. The prepared catalyst was used in the Fenton tests. The effects of the amount of the catalyst, pH of the solution, hydrogen peroxide (H2O2) concentration, dye concentration, temperature and reaction time on the process were studied and the optimum conditions were determined. The decolorization efficiency of 98% was obtained under the optimum conditions (pH = 2, amount of catalyst = 4.0 g/L, temperature = 30 degrees C, H2O2 concentration = 50 mM, time = 60 min). The decolorization kinetics of RY15 was also investigated. It was determined that the decolorization of RY15 obeyed the zero-order kinetics. Finally, reusability of the catalyst was investigated. The results show that the Fe/CuO catalyst is useful for the heterogeneous Fenton systems.