WO3 and electrochemical reduced graphene oxide (WO3/rGO) nanocomposites were prepared by one-step facile electrochemical deposition in an aqueous electrolyte containing tungsten species and graphene oxide. The WO3 in the as-prepared WO3/rGO composite is amorphous and exists in the form of nanostructure. Raman spectra confirm the co-existence of WO3 and the reduction of the graphene oxide sheets in the WO3/rGO composite. The electrochromic properties of the WO3/rGO film show significant improvement compared to WO3 films. The WO3/rGO film shows faster switching time, longer cycle life and larger coloration efficiency at the wavelength of 632.8 nm. These enhancements are mainly due to the synergistic incorporation of rGO into WO3. (C) 2013 Elsevier Ltd. All rights reserved.