This paper describes the synthesis and the characterization of ZnO nano-rods by laser ablation in a high temperature background gas. Two unique nano-structured ZnO crystals were obtained. One is a nano-wire pig-tailed ZnO nano-rod which has a nano-wire of less than 100 nm in diameter at the hexagonal top of nano-rods. Another is a ZnO nano-cone with a bottom diameter of 500 nm and a height of 2 mu m. The unique geometrical shapes may have a great potential in the application to the field emission devices and nano-optics. (c) 2005 Elsevier B.V. All rights reserved.