A new type of small diameter metallic nanowires decorated on carbon nanospheres have been developed and evaluated as catalysts toward the oxygen reduction reaction for polymer electrolyte fuel cell (PEFC) applications. The carbon nanospheres were modified with nanowires of Pt or bimetallic PtCo using a simple scalable wet chemical synthesis procedure. The resulting Pt-NW/C and PtCo-NW/C nanostructures were used to prepare catalyst ink using a Nafion solution. The ink was deposited on a rotating ring-disk electrode (RRDE) and their oxygen reduction electrocatalysis has been studied using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The nanowire morphology of the new structures feature very high mass activity, compared to that of the XC-72 Pt/C catalyst commercially available. The bimetallic PtCo-NW/C nanostructures possess the lowest Tafel slope, mass activity and near four-electron reduction kinetics for direct conversion of oxygen to water. (C) 2016 The Electrochemical Society. All rights reserved.