This paper presents our analysis of the mass transfer phenomena in fuel cells. Our attention was specifically focused on the parameter identification problems (briefly identification problems) related to the interpretation of the experimental data on the limit current. Two factors work together to make the interpretation of the limit current data difficult: the presence of two interacting electrodes (electrode coupling phenomena) and the flow rate changes along each electrode. The first effect can be well defined and understood by Studying reagent-poor inlet flow rates to the electrodes: the second effect can be analysed by superimposition. In this analysis, the asymptotic solutions for complete decoupling conditions, that are complete anodic (or cathodic) mass transfer control, have been shown to be very useful reference tools. (C) 2008 Elsevier B.V. All rights reserved.