Cermet-composites are at present under study as SOFC electrodes. Il the electrode composition, granulometry, thickness is accurately chosen performance are greatly enhanced over that of electrode composed only of electronic conduction particles. In our work the study of the electrode behavior as a function of the above mention parameters will be presented and discussed on the basis of model simulation and preliminary experimental results. The simulation model is an analytical tool whichh considers the electrode as a continuos and homogeneous, formed of two solid interface phases characterized by high electronic and ionic conductivities respectively. The experimental data have been obtained with Pt/YSZ cathodes in air, analyzed by means of impedance spectroscopy techniques applied to a typical three electrode configuration.