The direct platinisation of a solid polymer electrolyte (Nafion(R) membrane) was realized by chemical reduction of a platinum salt. The Pt-PEM electrodes thus obtained were modified by tin to improve the electrocatalytic activity towards the electrooxidation of ethanol. The Pt-PEM and Pt-Sn-PEM electrodes were characterized by TEM, EDX and XRD analysis, cyclic voltammetry, and their polarisation curves for the electrooxidation of ethanol were determined under quasisteady state conditions.