CuO shuttle-like nanocrystals were synthesized by the hydrolysis of cupric acetate (Cu(CH3COO)(2)center dot H2O) via a simple surfactant-assisted hydrothermal route at low temperature. It is found that the copper source, reaction temperature, reaction time, and surfactant cetyltrimethylammonium bromide (CTAB) are of importance to form the shuttle-like aggregates made by nanocrystals. A possible oriented-attachment mechanism for these aggregates is proposed based on their shape evolutions. (c) 2006 Elsevier B.V. All rights reserved.