In this study we report the use of a novel high resolution and high contrast X-ray Computed Tomography to image changes in the internal morphology, Pt distribution and carbon content of the fuel cell membranes subjected to the drive cycle testing with and without stop/start (depolarization/polarization) cycles. Membrane electrode assembly samples were imaged in air with minimal sample preparation and morphological disturbance. X-ray Computed Tomography revealed a redistribution of Pt within the cathode, migration of Pt into the electrolyte membrane and significant amounts of carbon corrosion