Effects of current density, CO2 pressure, and charge passed on the electrochemical reduction of gas phase CO2 under high pressure (< 50 atm) on a gas diffusion electrode containing Pt electrocatalysts were investigated. The faradaic efficiency for CO2 reduction reached 46% at a current density of 900 mA cm(-2). Methane was produced at a faradaic efficiency of 35%. A partial current density of 313 mA cm(-2) was achieved for methane formation. Ethanol was also produced ata faradaic efficiency of 2.2% (partial current density of -19.8 mA cm(-2)). The faradaic efficiency for methane formation increased with increasing CO2 pressure, whereas that for hydrogen formation decreased.