The nature of the solid electrolyte and the low electrode-electrode gap in polymer electrolyte fuel cells (PEFCs) makes it difficult to introduce a reference electrode into the fuel cell in order to separate anodic and cathodic overpotential contributions. A suitable experimental setup should not disturb the current distribution in the fuel cell. In order to satisfy the boundary conditions, we introduced a pseudo reference electrode into the fuel cell. With this setup, we have measured the impedance of both electrodes separately with respect to the pseudo reference electrode at different current densities. A state-space model was used to study the hydrogen oxidation reaction in order to identify kinetic parameters. (c) 2005 Elsevier Ltd. All rights reserved.