The proton exchange membrane fuel cell (PEMFC) is usually operated at elevated pressure, requiring the use of a compressor. Also the operating temperature is low, generally below 80 degreesC. For many applications, a somewhat higher operating temperature would be preferable. This paper describes the reasons for pressurised operation at, or close to, 80 degreesC in terms of water and heat management issues. It is concluded that a new type of proton conducting material is highly desirable, having many of the good Nation properties, but based on a proton conduction mechanism that does not require the presence of large amounts of water in the electrolyte. (C) 2003 Elsevier Science B.V All rights reserved.