Catalytic wet oxidation (CWO) of phenolic waste-water containing phenol, o-cresol, and 2,5-dimethylphenol was carried out in a batch reactor (phenolics = 10 g/L, chemical oxygen demand (COD) = 26 000 mg/L, and total organic carbon (TOC) = 7900 mg/L). Using the Box-Behnken experimental design (BBD) approach, the following optimum CWO conditions (catalyst: 5% Cu/AC) for phenolics degradation were found: C-cat = 3.4 g/L, T = 148 degrees C, P-O2, = 0.61 MPa, and pH = 7.4. Under these conditions, TOC and COD removals of 88 and 90%, respectively, were obtained after 4 h of reaction. p-Benzoquinone and hydroquinone were identified as major intermediates, whereas a mixture of carboxylic acids was detected in treated wastewater. At higher oxygen pressures (stoichiometric and above), mineralization of phenolics was improved although the overall degradation was lower probably due to overoxidation. Reaction kinetics, reusability of the catalysts, and detailed characterization of spent catalysts are also discussed in this paper.