The impact of land width and channel span on fuel cell performance was tested on 50 cm(2) flow fields. Combinations of land widths and channel spans of 0.25, 0.5 and 1.0 mm were evaluated. Polarization curves and high-frequency resistance were measured for several humidity levels for each of the flow fields. For performance at high current density, the land width was found to be the dominant factor. Reductions to the smallest size tested (0.25 mm) continued to showed improvement over wider lands. Adequate land fraction (preferably about 50%) needs to be provided to minimize contact resistance. (C) 2011 Elsevier B.V. All rights reserved.