Platinum dendrites were synthesized with the controlled sizes of 13-53 nm, and their electrocatalytic properties were evaluated for oxygen reduction reaction (ORR). Dendrites showed a superior activity for ORR and better selectivity for the production of H2O, compared to commercial E-tek catalysts. Durability was also tested by estimating the change in electrochemically active surface area (ECSA) after extended periods of oxygen reduction. Dendrites with larger sizes showed improved durability. (C) 2010 Elsevier B.V. All rights reserved.