In this paper, cerium oxide hollow nanospheres have been prepared via a polymer-monomer self-assembly route; it may be possible to extend this approach to fabricate other metal oxide hollow nanospheres. In this method, cerium oxide hollow nanospheres were fabricated by calcining hollow polymer spheres which were prepared via addition of eerie ammonium nitrate (CAN) into self-assembled micelles which were prepared through dissolving chitosan (CS) in methacrylic acid (MAA) solution.