Nanocrystalline TiO2, photocatalysts of different anatase to rutile ratios with high surface area have been prepared by sol-gel technique using titanium(IV) isopropoxide as the precursor. The prepared materials were characterized by XRD, BET, UV-vis, FT-IR, SEM and TEM techniques. Reaction parameters, such as hydrolyzing agent, molar ratio, aging time and calcination temperature were varied during the synthesis in order to get uniform nanosize TiO2, particles. XRD, SEM and TEM observations confirmed the nanocrystalline nature of TiO2. The band gap value and surface area were higher, whereas particle size of nano TiO2 was lower than the commercial TiO2 (Degussa P-25). The photocatalytic activity of nano TiO2 was evaluated in the phtocatalytic oxidation of bisphenol-A as a model reaction. Under the optimum conditions, nano TiO2 showed higher photocatalytic activity for the degradation of bisphenol-A than commercial TiO2 (Degussa P-25). (c) 2007 Elsevier B.V. All rights reserved.