The effects of carbon supports for platinum-ruthenium (Pt-Ru) catalysts on anode performance of direct methanol fuel cells (DMFC) were investigated. Good polarization characteristics of the methanol electrode were obtained for a Pt-Ru catalyst supported on an acetylene black with high specific surface area and a pore size distribution in the range of 3 to 8 nm. The performance of the methanol electrode increased with the increase in pore volume for the pore size distribution of 3 to 8 nn. Analyses of various carbon blacks and supported catalysts were carried out with several techniques : N-2 adsorption (Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods), CO adsorption, transmission electron microscope, and scanning electron microscope observations. The effects of the heat-treating temperature, time, and atmosphere on the polarization curves of the methanol electrodes with the acetylene black were investigated. The heat-treatment in air at 370 degrees C improved not only methanol oxidation but the durability of the Pt-Ru catalyst.