Solid-oxide fuel cells (SOFC) made of conventional materials with coplanar interdigitated electrodes located on the same side of the electrolyte have been fabricated and tested in a uniform mixture of methane and air in order to evaluate the influence of various operating parameters on cell performances. Anode thickness of several hundred micrometers is required to reach good cell stability. Also, the relative positioning of the electrodes in regard to the gas flow should be optimized as the gas composition is modified after passage over the anode. This aspect is particularly important with stacked cells, due to the modification of the gas composition in the upstream portion of the stack. Enhanced performances of the single-side cell were obtained by decreasing the width of the electrodes and their spacing, which both have the effect of reducing the ohmic loss. Following this approach, performances of 40 mW cm -2 were recorded at 800°C using electrodes of 0.5 X 8 mm separated by a gap of 0.2 mm.