Cu and Ni nanowire arrays were fabricated by potentiostatic electrodeposition into track-etched polycarbonate (PC) membranes. The diameters of nano-sized cylindrical pores in PC membranes varied from 15 to 200 nm. The transient current variation was divided into four stages during the growth of Cu and Ni nanowires. The nanowires were observed with FE-SEM and TEM. The aspect ratio of nanowire reached from 50 to 400. The diameters of nanowires were not perfectly uniform along the length. A knurled type of morphology was observed on the surface of nanowire with 15 nm diameter. Such a morphological variation was not governed by the overpotential, but attributed to the original shape of nanopore wall in PC membranes track-etched with heavy ions. (c) 2005 Elsevier B.V. All rights reserved.