We describe a facile solution-phase route for the synthesis of shape-controlled CuO nanocrystals. Modulating the adding temperatures of precipitator is shown to have a significant effect on the shapes of the obtained nanocrystals. The resulting shapes of the novel structures are diverse, including rods, belts, spindles, and spheres, all of which being obtained without any additional surfactants. Furthermore, different shapes of obtained CuO nanocrystals exhibit different Raman properties. (C) 2007 Elsevier B.V. All rights reserved.