This paper presents the performances of 4 cm 2 supercapacitors cells assembled with 200 mum thick active material films composed with activated carbon and carbon nanotubes mixture in organic electrolyte. Galvanostatic and electrochemical spectroscopy impedance measurements have been carried out. Galvanostatic measurements show that both internal resistance and specific capacitance decrease when the carbon nanotubes content increases in the active material. With 15% of carbon nanotubes, the internal resistance is 0.65 Omega cm(2) and the specific capacitance is 90 F g(-1) measured at 20 mA cm(-2). This performances remain stable during 10,000 cycles. The characterization of the frequency behavior was made by Electrochemical Impedance Spectroscopy. For 15% of CNTs content in the active material, the relaxation time (rho = -45degrees) is divided by 3 as compared to a supercapacitor using pure activated carbon electrodes. (C) 2004 Elsevier B.V. All rights reserved.