Electrochromic devices have increasing application in large-area display devices, switchable mirrors and smart windows. A variety of vacuum deposition technologies have been used to make electrochromic devices. The sol-gel process offers an alternative approach to the synthesis of low-cost, high-quality electrochromic device layers. This paper discusses the developments in sol-gel-deposited electrochromic films and a prototype;all sol-gel device with switching from 80% to 50% (550 nm). The sol-gel process involves the formation of oxide networks upon hydrolysis-condensation of alkoxide precursors. In this study, we cover sol-gel-deposited oxides of WO3, TiO2, Nb2O5, V2O5, Ni(OH)(2), Co(OH)(2) and CuOx. The coloration reaction voltammetry and spectral optical properties are presented for selected films. (C) 1998 Elsevier Science B.V. All rights reserved.