Photocatalytic decolourization of methylene blue dye under visible light has been investigated using vanadium modified titanium dioxide supported on zeolite (V-TiO2/zeolite). The photocatalyst was prepared and characterized by X-ray diffraction and SEM. The rate of photobleaching of dye was monitored spectrophotometrically. The effect of pH, dye concentration, amount of photocatalyst and intensity of light on the rate of photocatalytic reaction was observed. The results show that the use of Vdoped TiO2 increases the rate of photocatalytic decolourization of methylene blue to 5.7 and 8.6 times for 1% and 2% loading, respectively. The photocatalytic mechanism of V-TiO2 catalyst has been tentatively discussed.