Goal of the current project is the analysis and quantification of aging/degradation processes of the membrane-electrode-assembly (MEA) of low temperature PEM fuel cells (LT-PEMFC) based on a joint experimental/simulation-based technique. Utilizing a 3D-simulation approach, suitably extended based on experimental aging/degradation studies, “virtual experiments” related to membrane aging and catalyst degradation are conducted for selected membrane-electrode-assemblies adopting different global platinum content and spatial platinum distribution patterns. Simulation results of the temporal/spatial evolution of degradation processes enable their correlation with geometrical cell details and local operating conditions. Validation of the transferability of the developed technique to the analysis and quantification of degradation phenomena in real-life PEM fuel cells is done via simulation of differently aged cells adopting industrial flow fields and comparison of the obtained results with experimental data.