Nanocrystalline TiO2 catalysts have been successfully prepared by a sol-gel process. The results indicate that the reaction parameters and titanium source (titanium isopropoxid, titanium tetrachloride and titanium tetrabutoxide) affect the photocatalytic activity. The materials are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, scanning electron microscopy and Brunauer-Emmett-Teller techniques. TiO2 particle prepared using TiCl4 is found to be the most active catalyst for photodecomposition of phenol under UV light. TiO2(TiCl4-600) shows the highest reaction rate (0.62 mg L-1 min(-1)) and 100% mineralization of phenol is achieved within 2 h. Also, the catalytic activity of TiO2(TiCl4-600) is found to be higher than Degussa P-25 photocatalyst. The photocatalytic performances are in the order TiO2(TiCl4-600) > TiO2(TB-600) > TiO2(TIP-600). Anatase form of TiO2 is more effective for photodegradation of phenol.