The effect of the preparation method of PtRu electrocatalysts and the chemical treatment of support on the performance for methanol electrooxidation has been studied. Carbon supported PtRu catalysts were synthesized from aqueous solution of H2PtCl6 and RuCl3 precursors by two different methods: colloidal (using NaHSO3) and impregnation. The carbon black Vulcan XC-72R was functionalised with H2O2 and HNO3. A commercial PtRu/C catalyst purchased from Johnson and Matthey was used as reference. The obtained electrocatalysts were characterized by XPS, XRD, TEM, EGA-MS, TGA and TXRF. Chronoamperometry in methanol and COads stripping experiments were conducted to check their electrocatalytic activity. Electrocatalysts obtained by the colloidal method and supported on functionalised carbon black with HNO3 and especially with H2O2, showed better performances (CO tolerance and superior methanol oxidation ability) than those obtained by the impregnation method and the commercial one. (C) 2006 Elsevier B.V. All rights reserved.