Extended and oriented nanostructures are desirable for many applications, but direct fabrication of complex nanostructures with well-aligned morphology, orientation and surface architectures remains a significant challenge. Here, we report a successful robust fabrication of titanium (Ti) and zirconium (Zr) oxide nanotubes by a simple electrochemical anodizing process without the use of any template. The nanotubes formed perpendicular to the metal substrates and had an open ended array of continuous, well-aligned conformation with various hole sizes, depending upon applied anodizing voltages and times. Both the TiO2 and ZrO2 nanotubes have a uniform diameter which may make them suitable for chemical sensing, catalysis, optical emission and nanoelectrode assembly for batteries and electrochemistry. Crown Copyright (C) 2007 Published by Elsevier B.V. All rights reserved.