Large quantities of ZnO nanorods have been synthesized by the seed-mediated method in the presence of polyethylene glycol at 90 degreesC. The products are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The as-grown ZnO nanorods are uniform with a diameter of 40-70 nm and length about 2 mum. The nanorods grew along the [001] direction. Possible roles of ZnO seeds and polymer in the growth of ZnO nanorods are also discussed. (C) 2004 Elsevier B.V. All rights reserved.