We report the performance of an air-breathing laminar flow-based fuel cell (LFFC) operated in alkaline and acidic media. These direct methanol fuel cells exhibit open-circuit potentials of 0.93 and 1.05 V in acidic and alkaline media, respectively, demonstrating the absence of methanol crossover in both media. The LFFCs perform better in alkaline media under identical reaction conditions due to improved reaction kinetics at high pH. Further electrochemical investigation of these differences in reaction kinetics at the anode and cathode is also reported. (c) 2006 The Electrochemical Society.