Direct feeding of biogas to SOFC, which is derived from municipal bio-wastes, has been tested in this research. Because biogas composition is strongly affected by the kind of organic wastes and the operational conditions of methane fermentation, it has been monitored for 100 days using gas Chromatograph in order to reveal the fluctuation of biogas composition and its influence on the SOFC performance. CH4/CO2 ratio in the raw biogas was in the range of 1.4-1.9 and had a tendency to decrease when the cattle dung slurry was fed into the reactor. Using anode-supported button cell, stable operation of direct-biogas SOFC was achieved at 800°C. Cell voltage above 0.8 V was recorded over 350 h at 200 mA cm-2.