Cost and durability are the major barriers to the success of the Proton Exchange Membrane Fuel Cells (PEMFCs), and reducing the platinum loading of the catalyst layer could reduce the cost of the device. Thus, in this work, long-term durability tests in constant-current mode were performed using single-cells of 25 cm² with Membrane Electrode Assemblies (MEAs) prepared with 20% Pt/C (BASF) catalyst and electrodes with platinum loadings of 0.4 and 0.1 mgPt.cm^-2. Different ionomer to carbon ratios were also studied with the electrodes containing 0.1 mgPt.cm^-2 of catalyst loading. To characterize the electrochemical and structural properties of the MEAs, cyclic voltammograms, electrochemical impedance spectroscopy and field-emission scanning electron microscopy were utilized before and after the long-term durability tests. Concerning the platinum loading, the electrodes prepared with 0.1 mg Pt cm^-2 have lost proportionally more electrochemical surface area than the ones prepared with 0.4 mg Pt cm^-2 but at the same time, the electrodes with the lowest platinum loading presented lower irreversible performance loss rate when using higher ionomer to carbon ratio. The analyses made by several electrochemical techniques have indicated that the raise of the ohmic and mass transport resistances are the factors that most contribute to the irreversible performance loss, meanwhile the charge transport resistance due to the electrodes flooding is the main responsible for the reversible performance loss. The proportion of ionomer in the catalytic layer was studied and it was possible to infer that the highest ionomer proportion studied has contributed to mitigate the MEA degradation, although it facilitates the occurrence of flooding in the electrodes. Finally, it was observed that the quality of the contact formed between the electrodes and the membrane has remarkable influence on the PEMFCs durability.