The performance decay of a solid polymer electrolyte direct ethanol fuel cell (DEFC) based on a Pt 3 Sn 1 /C anode catalyst during an endurance test has been investigated. The effect of different cell shut-down procedures on the cycled behaviour of the DEFC has been studied. To get specific insights into the degradation mechanism, polarization and ac-impedance spectroscopy studies have been carried out. These analyses have been complemented by post-operation transmission electron microscopy and X-ray diffraction studies. The combination of these techniques has allowed to get information on recoverable and unrecoverable losses. This provides a basis for further improvement of DEFC components.