BACKGROUND: An ultraviolet light-emitting diode (UV-LED) was used in this investigation as the light source for the photocatalytic decomposition of o-cresol in aqueous solution because of its efficiency, design flexibility, and durability. The UV light intensities of the corn-shaped LED tube designed in this investigation were relatively uniform due to the correct arrangement of LEDs. RESULTS: For experiments conducted with initial o-cresol concentrations of 9mgL(-1) and pH 3, more than 80% of o-cresols were decomposed after 8h of irradiation. The calculated photonic efficiency (about 1.06%) for experiments conducted with continuous illumination was much lower than those (1-69-6-27%) obtained with periodic illumination. CONCLUSION: The proposed Langmuir-Hinshelwood kinetic model with modification of UV light intensity attenuation could be adequately applied to describe the temporal behavior of the o-cresol decomposition in aqueous solution by the UV-LED/TiO2 process. (c) 2007 Society of Chemical Industry.