In this work, we report a simple one-pot hydrothermal approach to prepare CeO2 hollow microspheres with a mean diameter of 1.5 mu m and a shell thickness of 90 nm. Structure and morphology of CeO2 hollow spheres were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), field-emission scanning electron microscope (FE-SEM), and N-2 adsorption-desorption. In the reaction system, L-asparagine and KBrO3 act as OH- provider and oxidizer, respectively. Reaction duration and L-asparagine content are shown to play important roles in the formation of the hollow structures. A hollowing mechanism is proposed based on the experimental results. (C) 2009 Elsevier B.V. All rights reserved.