A lab-scale proton exchange membrane fuel cell (PEMFC) is investigated at automotive operating condition. The comparison of straight-parallel PEMFC and serpentine PEMFC is carried out with detailed description of these flow-field configurations. A three-dimensional model is developed taking into account electrochemical reaction and evaporation/condensation of water which can affect on the overall flow field. The straight-parallel PEMFC has considerably low internal pressure drop which is beneficial to automotive application. Non-uniform temperature and current density distributions due to flow maldistribution are identified as a challenge to the straight-parallel PEMFC. To improve uniformity of these variables, we conducted an investigation on the manifold parameters. The result indicates that the wider manifold configuration has better cell performance as well as more uniform temperature and current density distributions than the narrower manifold configuration. This is primarily caused by improved uniformity on the flow velocity profile among parallel channels. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.