Mesoporous catalyst support based on tin oxide (SnO2) is synthesized with high surface area of 205 m(2) g(-1) and with narrow pore size distribution. Modified polyol method is used to deposit platinum on SnO2. The physical properties of the support and the SnO2-supported Pt catalyst (Pt/SnO2) are characterized by using the Brunauer, Emmett, and Teller method, X-ray diffraction, and transmission electron microscopy. The electrochemical stability and durability of the Pt/SnO2 catalyst are investigated by the accelerated stress tests proposed by the U.S. Department of Energy. Pt/SnO2 catalyst exhibits electrochemical activity in fuel cells comparable to that of Pt/C. More importantly, the electrochemical stability of the Pt/SnO2 catalyst significantly improves when compared with the commercial Pt/C catalyst at high potentials (similar to 1.2 V vs reversible hydrogen electrode). (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3442371] All rights reserved.