Pure phases of a new oxyarsenide superconductor of the nominal composition CeFe0.9Co0.1AsO were successfully synthesized by solid state reaction in sealed silica ampoules at 1180 {ring operator}C. It crystallizes in the layered tetragonal ZrCuSiAs type structure (sp gp P 4 / n m m) with lattice parameter of ' a ' = 3.9918 (5) Å and ' c ' = 8.603 (1) Å. A sharp superconducting transition is observed at 11.31 K (± 0.05 K) with an upper critical field of 45.22 T at ambient pressure. The superconducting transition temperature is drastically lowered (∼ 4.5, 4.9 K) on increasing the concentration (x = 0.15, 0.2) of cobalt. © 2008 Elsevier Ltd. All rights reserved.