We report the synthesis and characterization of new oxypnictides of the type Ce 1-xYb xO 0.9F 0.1FeAs ('x' = 0.3, 0.4 and 0.5) for the first time. All these compounds crystallize in the tetragonal ZrCuSiAs type structure (space group: P4/nmm). Reduction in both the lattice parameters (a and c) was observed on substitution of smaller Yb ions at Ce sites in CeO 0.9F 0.1FeAs. All these compounds were found to be superconducting with maximum T c of 48.7 K for 'x' = 0.5 composition which is highest among Ce(O/F)FeAs based superconductors. Temperature dependence of resistivity under magnetic field has been studied to evaluate the upper critical field (H c2(0)) of these superconductors. Enhancement in upper critical field (H c2) was observed for these Yb doped Ce 1-xYb xO 0.9F 0.1FeAs superconductors (max H c 2(0) = ∼142 T for 'x' = 0.3). The average coherence length of all Yb doped samples was estimated to be ∼23 Å. © 2012 Elsevier B.V. All rights reserved.