This work reports sectional electrochemical impedance (EIS) measurements of a high temperature polymer electrolyte membrane (HTPEM) fuel cell. These measurements were taken using a high temperature stable polybenzimidazole membrane electrode assembly (MEA) doped with phosphoric acid (PBI/H3PO4). Three different types of flow-fields (namely, a six channel parallel serpentine flow-field, a parallel straight flow-field, and a mixed-type flow-field) were analyzed in gas counter-flow and co-flow configuration under selected operating conditions. The current density distribution was also measured, and the results were presented to highlight the dominant factors that lead to inhomogeneous distributions. The results showed that the distribution mainly depended on the availability of oxygen, overlapped by the fluid-flow distribution. The situation changed once a carbon monoxide (CO) enriched gas was used at the anode side. In this case, the current density distribution decreased close to the cathode inlet and increased near the anode inlet. At high CO concentrations, the highest current densities were found close to the anode inlet. Sectional EIS measurements supported these observed trends and confirmed that the segments close to the anode inlet had a lower charge transfer resistance with a higher charge transfer resistance at segments closer to the anode outlet. (C) 2013 Elsevier Ltd. All rights reserved.