In the present paper, PtRu electrodes are used to study the electrooxidation of ethylene glycol (EG) in acid medium. The voltammetric results show that current-potential curves are shifted by about 0.2 V towards more negative potentials through the promoting effect of Ru on Pt. As in the case of pure platinum, FTIR spectra on PtRu surfaces prove that CO2, glycolic acid and, possibly, oxalic acid are formed in parallel reactions. The catalytic activity, measured as the current density at constant potential, increases with the Ru content. But the complete oxidation of EG to CO, is favored by a high Pt content. In order to compare the catalytic activity of different PtRu compositions, currents measured at electrodeposited electrodes are normalized using the data for the oxidation of a CO monolayer.Results of a test using a laboratory PEM EG/O-2 cell with Pt:Ru (50:50) are presented. (C) 2003 Elsevier Ltd. All rights reserved.