In this work, results for the electrocatalysis of CO and methanol electro-oxidation are discussed considering the validity of the extrapolation of results obtained in fundamental electrochemical systems to operational low-temperature fuel cells (DMFC). It is concluded that the performance of the catalysts depends not only on obvious parameters, like the composition, but also on the method of preparation, subsequent treatments, and even on the nature of the metal precursors. Furthermore, the results show that parameters of the supported catalyst, like particle size, may not be as important as a uniform distribution of the particles on the support obtained with a clean method of preparation. The conclusion is that much progress is still needed in the understanding of the behaviour of the catalysts, particularly bimetallic and multimetallic catalysts in order to extrapolate results obtained in fundamental systems to practical systems. At present, the only real test of a given catalyst seems to be the evaluation of the performance in an actual fuel cell. (C) 2003 Elsevier Ltd. All rights reserved.