In this study, advanced oxidation technologies, namely Fenton Process (FP), Fenton-Like Process (FLP), ozonation (O-3) and O-3/H2O2 processes, were applied to synthetic wastewater containing 3-indolebutyric acid (IBA). The effectiveness of each process was investigated at different pH values, Fe+2, Fe+3, O-3 and H2O2 concentrations with respect to the removal efficiencies for chemical oxygen demand (COD) and total organic carbon (TOC). The best removal efficiencies were seen at pH 3 and 2 mM Fe concentration in both FP and FLP, in which the optimum H2O2 concentrations were 6 mM for FP and 10 mM for FLP. Optimum process conditions were pH 12 for the O-3 process, pH 9 for the O-3/H2O2 process and 1:1 O-3/H2O2 molar ratio. The highest COD removal efficiency was 86 percent, obtained in the O-3/H2O2 process and the highest TOC removal efficiency was obtained at 77 percent in the FP. Water Environ. Res., 84, 100 (2012).