In this paper, we report on the synthesis of ZnO nanowires via templated electrochemical deposition. The deposition was performed in a classical three electrodes electrochemical cell and the samples were mounted as a working electrode. A polycarbonate membrane with random distribution of nanometric pores was used as the working electrode. The morphology analysis and structure characterization of the ZnO nanowires with different diameters were carried out using conventional transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) techniques. The electrons diffraction patterns confirm that those ZnO nanowires have the same crystal structure as the electrodeposited ZnO thin films indexed by XRD: hexagonal Wurtzite structure with cell parameters a = 0.326 and c = 0.523 nm. Both electron diffraction and HRTEM investigations reveal a single crystalline structure of the electrodeposited ZnO nanowires. It is noted that the ZnO nanowires have no preferential growth direction. A surface roughness of few nanometers of the nanowire was observed, probably due to surface roughness inside the nanometric pores. An obvious discrepancy between the nominal pore size and the measured wire diameter is revealed. (c) 2005 Elsevier B.V. All rights reserved.