High temperature polymer electrolyte membranes are being sought for PEM fuel cells in order to increase fuel poison tolerance, reduce sensitivity to variations in relative humidity, and simplify various components of the fuel cell system. These new polymers are likely to operate under much dryer conditions than currently-available lower temperature polymers like Nafion. Even at higher temperatures, the oxygen reduction reaction is still the performance limiter, and the effect of the dry conditions on this reaction is unknown. This talk will describe a novel experimental technique to study a gas/ion electrochemical reaction at a metal/polymer interface under conditions simulating that of the fuel cell. The technique was applied to study oxygen reduction reaction (ORR) at the Pt/PBI/phosphoric acid interface. Results of the study and interpretation of the kinetic data will be presented.