Homogeneous and transparent V2O5-TiO2 composite nanometer thin films were prepared on glass substrates by sol-gel processing and dip-coating technique. The films as well as the dried powder of bulk gel were characterized by different techniques like X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM), atomic force microscope (AFM) and thermogravimetry-differential thermal analysis (TG-DTA). The hydrophilicity of the films was determined by measuring the water contact angles on the films. The results showed that the dopant of V2O5 on TiO2 thin films could produce a visible-light response to the films, and the introduction of V2O5 could suppress the structural phase transition and crystal growth of TiO2 crystal. Finally, the relationship between crystalline size and hydrophilicity under sunlight was investigated in this article. (C) 2004 Elsevier B.V. All rights reserved.