Four designs of flow fields were applied to micro-proton exchange membrane fuel cells (mu-PEMFCs) using microelectromechanical system (MEMS) technology. The flow fields and membrane electrolyte assembly (MEA) of 2.25 cm(2) active area were assembled to mu-PEMFCs. Electrochemical behaviors of these mu-PEMFCs were investigated by polarization method at reactants flow rates of 15 ml min(-1), 30 ml min(-1) and 50 ml min(-1), respectively. This study emphasized the effects of different topologies of flow fields on performance of mu-PEMFCs. Results demonstrated that mu-PEMFCs with different flow fields have similar behavior at reactants flow rates of 50 ml min(-1). However, at reactants flow rates of 15 ml min(-1) and 30 ml min(-1), performance of the mu-PEMFC with long and narrow micro-channels rapidly deteriorated due to the flooding in micro-channels. The mixed serpentine design had a good ability to resist the flooding, but it displayed a low maximum power density because of its short effective length of micro-channels. The results in this study suggested that the mu-PEMFC with a mixed multichannel design flow field and long micro-channels yielded the best performance. (C) 2009 Elsevier B. V. All rights reserved.