Samarium-doped ceria (SDC) is coated onto a Ni/yttria-stabilized zirconia (Ni/YSZ) anode for the direct use of methane in solid-oxide fuel cells. Porous SDC thin layer is applied to the anode using the sol-gel coating method. The experiment was performed in H-2 and CH4 conditions at 800 A degrees C. The cell performance was improved by approximately 20 % in H-2 conditions by the SDC coating, due to the high ionic conductivity, the mixed ionic and electronic conductive property of the SDC, and the increased triple phase boundary area by the SDC coating in the anode. Carbon was hardly deposited in the SDC-coated Ni/YSZ anode. The cell performance of the SDC-coated Ni/YSZ anode did not show any significant degradation for up to 90 h under 0.1 A cm(-2) at 800 A degrees C. The porous thin SDC coating on the Ni/YSZ anode provided the electrochemical oxidation of CH4 over the whole anode, and minimized the carbon deposition by electrochemical carbon oxidation.