We report for the first time the growth of tetrapod-shaped ZnO microtubes synthesized via a simple method. The tetrapod-shaped ZnO microtubes were synthesized from mixtures of high-purity Zn powder and activated carbon in a crucible at 930-940 degrees C in air without the presence of any catalyst. The ZnO microtubes were found to be grown on the arrays of ZnO microcrystals, which were horizontally grown from the inner walls of crucibles. Optical and scanning electron microscopy were utilized to observe the morphologies of the tetrapod-shaped ZnO microtubes, and X-ray diffraction was employed to study the crystal structure. The microtubes were found to be hexagonally shaped with well-defined side faces. A growth model was proposed to explain the formation of the tubular ZnO microcrystals. (C) 2007 Elsevier Ltd. All rights reserved.