This study performs numerical simulations to investigate the effects of buoyancy on the gas flow characteristics, temperature distribution, electrochemical reaction efficiency and electrical performance of a proton exchange membrane fuel cell (PEMFC) with a novel wave-like gas flow channel design. in general, the simulation results show that compared to the straight geometry of a conventional gas flow channel, the wave-like configuration enhances the transport through the porous layer and improves the temperature distribution within the channel. As a result, the PEMFC has an improved fuel utilization efficiency and an enhanced heat transfer performance. It is found that the buoyancy effect increases the velocity of the reactant fuel gases in both the vertical and the horizontal directions. This increases the rate at which the oxygen gas is consumed in the fuel cell but improves the electrical performance of the PEMFC. The results show that compared to the conventional straight gas flow channel, the wave-like gas flow channel increases the output voltage and improves the maximum power density by approximately 39.5%. (c) 2007 Elsevier Ltd. All rights reserved.