This study examined the material and electrochromic properties of vanadium-titanium oxides (V-Ti oxides) as a counter electrode material in electrochromic devices. These oxides were deposited on an ITO substrate using a co-sputtering method at different levels of RF power. Electrochemical experiments of these oxides were carried out using half-cell and semi full-cell tests which are good methods for measuring the potential applied to each electrode. The change in electrochromic properties after 1000 cycles of a semi full-cell test was examined. Reversibility and durability of an electrochromic device were improved by increasing the titanium content in V-Ti oxides. (C) 2009 Elsevier B.V. All rights reserved.