Supported electrolyte-membrane-type solid oxide fuel cells (SOFCs) were prepared by a co-fire process using Zr(Sc)O-2 (SSZ) and Ce(Gd)O-2 (GDC) as electrolyte. Electrolyte films were prepared on supports, such as a mixture of Ni and electrolyte, by electrophoretic deposition (EPD) method and then co-fired. It was concluded that co-firing of GDC electrolyte cell would not be feasible because of its fragility during sintering and cell operation. The co-firing of SSZ cells (Ni--SSZ/SSZ/Pt-SSZ) gave successful results. The Optimum power density was 1.8, 1.2, 0.4, and 0.1 W/cm(2) at 900, 800, 700, and 600 degreesC, respectively. Further improvement of the electrode will make the cell operation even at 600 degreesC feasible. However, improvement of the cathode using (La,Sr)CoO3 (LSC) was unsuccessful due to the formation of an insulating layer with SSZ. The insertion of GDC protective layer (2 mum) between SSZ and LSC cathode was examined, but the results were worse than the case of Pt-SSZ cathode. It may be due to the formation of a poor conducting layer between GDC, LSC and SSZ.