The effect of nanoparticle addition into an anode electrode on direct ethanol fuel cells is reported. When nanopartilces such as TiO2, SnO2, and SiO2 were added to the anode electrode, the short circuit current (J(sc),) increased from 2.8 to 4.4-9.0 mA cm(-2). The nanoparticle and the carbon-supported PtRu (PtRu/C) were mixed merely at the ratio of 1:1. The PtRu content decreased to a half of the original electrode, but, J(sc) increased after the nanoparticle addition. The results were explained by the increase in the fuel diffusion and the catalyst activity. These effects of the nanoparticle addition were not observed for direct methanol fuel cells.