In this paper, a two-phase non-isothermal PEM fuel cell model based on the previously developed mixed-domain PEM fuel cell model with a consistent treatment of water transport in MEA has been established using the traditional two-fluid method. This two-phase multi-dimensional PEM fuel cell model could fully incorporate both the anode and cathode sides, properly account for the various water phases, including water vapor, water in the membrane phase, and liquid water, and truly enable numerical investigations of water and thermal management issues with the existence of condensation/evaporation interfaces in a PEM fuel cell. This two-phase model has been applied in this paper in a two-dimensional configuration to determine the appropriate condensation and evaporation rate coefficients and conduct extensive numerical studies concerning the effects of the inlet humidity condition and temperature variation on liquid water distribution with or without a condensation/evaporation interface. (C) 2007 Elsevier B.V. All rights reserved.