Carbon nanotubes/Prussian blue (CNT/PB) films were prepared and tested as electrodes for electrochemical devices. The thicknesses (and transmittances) of the different films were controlled through the amount of both CNTs and PB. The electrochromic behavior of the films was compared to a PB film electro-synthesized by the classical route, showing improvement in several parameters, mainly the stability towards electrochemical cycles. The five different CNT/PB films presented Coulombic efficiency between 91 and 94%, coloration efficiency between 61.1 and 138.6 cm(2) C-1, response time between 1.1 and 3.2 s and oxidation/reduction charge between 0.17 and 0.69 mC cm(-2). The combination of the electrochromic parameters and high stability should enable the CNT/PB films to be suitable for technological applications. (C) 2012 Elsevier B.V. All rights reserved.