In this work, we report the improvements made on the PEM fuel cell with metal foam as the flow distributor. The comparison in polarization curve is made between the PEM unit cell with different metal foam flow field designs and the PEM unit cell with graphite bipolar plate as flow distributor. The experimental results show that after using improved metal foam flow field designs, the fuel cell's performance increases. Our results show that, in the PEM unit cell with single zone metal foam, the convection is weak at side corners. Dividing the metal foam into multiple regions and using multiple inlets effectively improves gas distribution. AC impedance measurement was also performed to study impedance characteristics. The Nyquist and Bode plots confirmed that Ohmic resistance, activation resistance, and mass transfer resistance of metal foam fuel cell are all smaller than that of conventional PEM unit cell. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.