Carbon supported Pt-Co-Sn has been evaluated as ternary catalyst for the oxygen reduction reaction (ORR) in acidic medium. The catalyst was prepared by impregnation method using NaBH4 as reducing agent. X-ray diffraction (XRD), X-ray fluorescence (XRF) and transmission electron microscopy (TEM) have permitted to investigate the structure, the elemental composition, the morphology and the size distribution of Pt-Co-Sn nanoparticles. Using the rotating disk electrode (RDE) technique, the electrocatalytic activity of the Pt-Co-Sn/C catalyst towards ORR was compared to Pt/C and to its binary counterparts, fabricated with the same synthesis method. From the RDE data and using the KouteckyLevich equation, it is found that the change in performance of the catalyst is in the following order: Pt-Co-Sn/C > Pt-Sn/C > Pt/C > Pt-Co/C. Moreover, O-2 reduction proceeds mainly through 4 electron pathway on all Pt based electrodes. (C) 2014 Elsevier B.V. All rights reserved.