Novel copper sulfide (CuS) hollow spheres composed of nanoflakes were synthesized under hydrothermal conditions by treating copper (II)-thiourea complex from CuSO(4)(.)5H(2)O and thiourea at 180degreesC for 24h. When increasing the reaction temperature, much smaller hexagonal CuS nanoflakes generated from copper (II)-thiourea complex formed and self-assembled into hollow spheres. The products were characterized by means of X-ray powder diffraction scanning electron microscopy and field emission scanning electron microscopy. It is found that the reaction temperature and copper (II)-thiourea complex are of importance to form hollow spherical superstructures. A possible mechanism is also discussed. (C) 2004 Elsevier B.V. All rights reserved.