Photocatalytic degradation of paraquat using mesoporous-assembled Cu-TiO 2/SBA15 under UV and visible light was investigated. The catalyst was synthesized by impregnation of Cu-TiO 2 colloids onto SBA-15. The colloids of Cu-TiO 2 were prepared via sol-gel method while the mesoporous support was prepared using hydrothermal technique. The catalyst was characterized using X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy, UV diffuse reflectance spectroscopy, Zeta potential and X-ray adsorption spectroscopy. Results from characterizations showed that Cu doped TiO 2 had a small crystalline size and was well-dispersed on SBA-15. The inclusion of SBA-15 significantly enhanced the photocatalytic activity of the catalyst. Among the three types of undoped catalyst in this study (P25, TiO 2, TiO 2/SBA-15), TiO 2/SBA-15 yielded the highest degradation of paraquat for all pH under UV illumination. Meanwhile 2 wt.% Cu-TiO 2/SBA-15 yielded the highest activity under visible light.