Mixed-reactants solid-polymer-electrolyte direct methanol fuel cells (SPE-DMFCs) with a PtRu/C anode and a methanol-tolerant oxygen-reduction cathode catalyst have been assembled and have been subjected to galvanostatic polarisation studies. The oxygen-reduction cathode was either of the FeTMPP/C, CoTMPP/C, FeCoTMPP/C and RuSe/C. It was found that the SPE-DMFC with the RuSe/C cathode yielded the best performance. It has been possible to achieve power densities of approximately 50 and 20 mW/cm(2) while operating a mixed-reactants SPE-DMFC at 90 degreesC with oxygen and air fed cathodes, respectively. Interestingly, these SPE-DMFCs exhibit no parasitic oxidation of methanol with oxygen. (C) 2003 Elsevier B.V. All rights reserved.