Vanadium oxide nanowires were prepared successfully by thermal evaporation onto ITO-coated glass at a pressure of 8 x 10(-4) Torr and 650 degrees C from vanadium oxide powders (V2O5 99.95%). The vanadium oxide nanowires-based electrochromic device (ECD) provides larger reaction surface area than thin film-based ECD to store more ions as working or counter electrode. Structure, morphological, and electrochromic properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammograms (CV), and UV-VIS spectroscopy. The diameter of vanadium oxide nanowires range from 10 to 100 nm and length up to several hundreds nanometers. The morphology and performance of vanadium oxide nanowires did not alter after 1000 reox-cycles observed by SEM and CV. (c) 2005 Published by Elsevier B.V.