Pure and (0.5-3 at%) vanadium doped TiO2 nanoparticles have been synthesized by wet chemical method. The as synthesized materials have been characterized by using XRD, atomic force microscope (AFM), Raman, EPR and UV-vis spectroscopy techniques. From XRD studies, both pure as well as vanadium doped TiO2 have been found to show pure anatase phase. The value of lattice constant c is smaller in doped TiO2 as compared to undoped and has been found to decrease with increase in vanadium concentration. AFM studies show formation of spherical particles with particle size ∼23 nm in all the samples. Photochromic behavior of these materials has been studied by making their films in alkyd resin. Vanadium doped TiO2 films show reversible change in color from beige-yellow to brownish violet on exposure to UV light. The mechanism of coloration and bleaching process has been discussed. © 2009 Elsevier B.V. All rights reserved.