A novel and simple technique was developed to measure current distribution in PEM fuel cells with serpentine flow fields. In this technique, a specially designed measuring gasket was inserted between the flow field plate and the gas diffusion layer, and the current at each sub-area of the fuel cell was measured by each of the current collecting strips on the measuring gasket. The current distribution measurement gasket was independent of PEM fuel cells, and can be used in any fuel cell without the need of a special fuel cell or modification of any component of an existing fuel cell. More importantly, this technique can be easily used to measure current density distribution in any cell or every cell in a fuel cell stack. In addition, this technique is very inexpensive, with the only additional cost being that of the measuring gasket. In this work, this measurement gasket technique was used to study the influences of humidification temperatures, cell operating temperatures, reactant flow rates, and operating pressures on current distributions in a PEM fuel cell. Local membrane hydration, reactant depletion and possible cathode flooding can be deduced from the measurement results, and some potential improvements in fuel cell designs are suggested. (c) 2005 Elsevier B.V. All rights reserved.