We investigated the mineralization of Cl Reactive Yellow 145 (RY145) in aqueous solution in a UV-enhanced ozonation (UV/O-3) reactor. The effects of several operational parameters, including solution pH, initial dye concentration, ozone feed, and bulk temperature, on total organic carbon (TOC) removal were investigated. The experimental results illustrated that ozonation combined with UV radiation for removal of TOC was more efficient than ozonation alone or UV irradiation alone. At an initial pH of 8.0, bulk temperature of 30 degrees C, ozone feed of 4.8 g/h, and initial dye concentration of 500 mg/L, the TOC removal efficiency of RY145 reached similar to 80% after 150 min under 175 W UV irradiation. Intermediates formed during RY145 mineralization were detected by gas chromatography coupled with mass spectrometry (GC/MS) and ion chromatography (IC). On the basis of our results, we propose a tentative degradation pathway.