Scanning photoelectron microscopy (SPEM) has been applied to study the processes at the interface between the oxygen ion conducting solid electrolyte YSZ (yttrium stabilized zirconia) and a microstructured 500 Angstrom thick Pt film on top of the YSZ when electrical potentials are applied. An electrochemically induced oxygen spillover onto the Pt surface has been observed upon electrochemical pumping with a positive potential applied to the Pt film. The spillover species was characterized in X-ray photoelectron spectroscopy by an Ols binding energy of 530.4 eV which is identical to that of chemisorbed oxygen from the gas phase.