The influence of the microstructure on the electrical properties and polarization behavior of thin porous ceramic electrode layers used in solid oxide fuel cells has been investigated. Thin layers (2-10-mu-m) of the cathode material Sr0.15La0.85MnO3 (15SLM) were film coated on YSZ substrates from classified suspensions. Narrow particle-size distributions in the suspension resulted in close-packed layers with a very homogeneous porosity and pore-size distribution. The specific conductivity of the layers decreased significantly with increasing porosity and mean pore size. A specific conductivity of 109 S . cm-1 was obtained at 1000-degrees-C for a 2.9-mu-m thick layer from a suspension with particles in the range 0.10-0.25-mu-m. The current-overvoltage behavior of the film-coated layers presented in this study did not, however, show any significant dependence on the thickness and the microstructure of the porous layers. Overvoltages (eta) at a current density of 0.1 A/cm2 at 898-degrees-C were quite low, i.e., in the range 60-70 mV. In comparison with other studies it is shown that film coating improves the microstructure of the ceramic electrode layers, which in turn lowers the cathodic overvoltages for the oxygen reduction reaction.