Performance of internal reforming SOFC was evaluated in the temperature range of 700-800°C for various biofuels. Three real biodiesel fuels (BDFs) and two pure fatty acid methyl esters (FAMEs) with different contents of unsaturated C-C bonds were fed directly to anode-supported SOFCs. The results demonstrated that in principle direct-feeding of BDFs into SOFC is viable, but the content of unsaturated FAMEs in BDF should be as low as possible. Direct feeding of BDFs caused carbon deposition which was more significant at lower operational temperatures and at higher contents of unsaturated FAMEs. On the other hand, biogas obtained by anaerobic fermentation of garbage, is suitable for SOFC operation because it contains natural reforming agent (CO 2). Stable operation of internal reforming SOFC running on biogas was achieved by the addition of adequate amount of air to biogas.