Aluminum oxide nanoparticles were prepared by the hydrolysis of aluminum oxide alkoxides followed by calcinations, in the presence of surface stabilizing agents, such as Na(AOT) molecules. The size of alumina precursors (bohemite) was 20-30 nm, yielding aluminum oxide particles with an average size of 80 nm after calcinations at 1200 degrees C. The shape of the alpha-alumina nanoparticles was mainly spherical and the high temperature inhibited the formation of the hexagonal crystals. The introduction of Na(AOT) during the appropriate processing step, had the effect of controlling the size of the particles, the degree of aggregation and the particles shapes. (C) 2005 Elsevier Ltd. All rights reserved.