Highly dispersed Pt nanoparticles supported on Vulcan XC-72R were prepared by a modified polyol reduction for low-temperature fuel cells. The modified polyol reduction was controlled with various concentrations of reducing agent and reduction times at 90 degrees C. The 20 wt% Pt/C catalyst prepared under an optimum reduction condition (reduction temperature = 90 degrees C, ethylene glycol/H2O volume ratio = 1, and reduction time = 10 h) exhibited the highest electrochemical active surface area (EAS) and methanol oxidation activity due to the small Pt nanoparticles (1.2 nm) with quite a narrow size distribution between 0.5 and 2 nm. The 40 wt% Pt/C catalyst was prepared using the optimum condition to confirm the applicability of the preparation method. The synthesized 40 wt% Pt/C catalyst had smaller-sized Pt nanoparticles (1.3 nm) and a higher EAS than that of a commercial 40 wt% Pt/C catalyst. With pure H-2 (anode) and air (cathode), a PEMFC using the synthesized 40 wt% Pt/C catalyst as a cathode had higher single-cell performance than that of the commercial catalyst. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.