Nanostructured CuO microspheres were prepared by a novel solid-stabilized emulsion for the first time. SEM, TEM, XRD, size analysis and BET measurement were used to characterize the CuO microspheres. The average diameter of the CuO microspheres was 2.8 mu m. The surfaces of the CuO microspheres were made of pin-like nanostructures with a pin diameter of 95 nm and a pin length of at least 600 nm. The XRD analysis indicated that the CuO nanostructured microspheres were of monoclinic lattice. The specific surface area of the CuO nanostructured microspheres was about 56.8 m(2)/g. A mechanism for the formation of the CuO microspheres with nanostructured surfaces was proposed. (C) 2006 Elsevier Ltd. All rights reserved.