The electrodeposition of platinum and ruthenium was carried out on carbon electrodes to prepare methanol anodes with different Pt/ Ru atomic ratios using a galvanostatic pulse technique. Characterizations by XRD, TEM, EDX and atomic absorption spectroscopy indicated that most of the electrocatalytic anodes consisted of 2 mg cm(-2) of Pt - Ru alloy particles with the desired composition and with particle sizes ranging from 5 to 8 nm. Electrochemical tests in a single DMFC show that these electrodes are very active for methanol oxidation and that the best Pt/ Ru atomic ratio in the temperature range used ( 50 - 110degreesC) is 80: 20. The influence of the relaxation time t(off) was also studied and it appeared that a low t(off) led to smaller particle sizes and higher performances in terms of current density and power density.