A two-dimensional, non-isothermal, anisotropic numerical model is developed to investigate the impact of the interfacial morphology between the micro-porous layer (MPL) and the catalyst layer (CL) on the polymer electrolyte fuel cell (PEFC) performance. The novel feature of the model is the inclusion of directly measured surface morphological information of the MPL and the CL The interfacial morphology of the MPL and the CL was experimentally characterized and integrated into the computational framework, as a discrete interfacial layer. To estimate the impact of MPL vertical bar CL interfacial surface morphology on local ohmic, thermal and mass transport losses, two different model schemes, one with the interface layer and one with the traditionally used perfect contact are compared. The results show a similar to 54 mV decrease in the performance of the cell due to the addition of interface layer at 1 A cm(-2). Local voids present at the MPL vertical bar CL interface are found to increase ohmic losses by similar to 37 mV. In-plane conductivity adjacent to the interface layer is determined to be the key controlling parameter which governs this additional interfacial ohmic loss. When the interfacial voids are simulated to be filled with liquid water, the overpotential on the cathode side is observed to increase by similar to 25 mV. Local temperature variation of up to 1 degrees C is also observed at the region of contact between the MPL and the CL, but has little impact on predicted voltage. (C) 2010 Elsevier B.V. All rights reserved.