Uniform NiO, α-Fe2O3, ZnO,CuO and Ga2O3 hollow nanospheres consisting of a shell of closely packed nanoparticles with a shell wallthickness of a few tens of nanometers have been successfully synthesized on alarge scale by controlled precipitation of metal cations with urea in the presenceof carbonaceous saccharide nanospheres as hard templates. In addition, itis interesting to find that the single-phase transition metal oxides of NiO andα-Fe2O3 can form ball-in-ball hollow nanoarchitectures by this simple approach. Furthermore, it isdemonstrated that direct size control of the oxide hollow nanospheres can be achieved byusing carbon templates of different diameters. This method could be extended to thesynthesis of many other metal oxide hollow nanospheres. The hollow nanostructuredmetal oxides might be found to have potential applications in many fields such ascatalyst supports, catalysis, drug delivery, chemical/biological separation, sensing,etc.