The preparation of a Pt-Co/C electrocatalyst for the oxygen reduction reaction in PEM fuel cells was achieved via a novel combined process of impregnation and seeding. The effect of seeding and non-seeding approaches on the morphologies and activities of the electrocatalyst was explored. The results indicated that the seeding or non-seeding approaches provided the similar results of Pt structure and phase composition in the Pt-Co/C electrocatalyst. However, the seeding approach provided a more uniform dispersion and smaller particle size of electrocatalyst compared with that of the non-seeding approach. Also, higher values of kinetic parameters including i(0), E(0), i(0.9V) and E(10mA/cm2) were obtained in case of seeding electrocatalyst. Finally, the rotating disk electrode experimental results showed that the mechanism of oxygen reduction involved the four-electron pathway. (C) 2010 Elsevier Ltd. All rights reserved.