Abstract Solid oxide fuel cells (SOFCs) with the construction of Ni-BaCe0.8Gd0.2O2.9 (BCGO)/BCGO/La0.5Sr0.5CoO3−δ (LSCO)–BCGO are reported. With commercial liquefied ammonia directly used as the fuel, the performance of a single cell was tested from 600 to 750 °C. The OCV was 1.102 and 0.985 V at 600 and 700 °C, respectively, which is fairly consistent with the theoretical values calculated on the assumption of ammonia completely decomposing. Also a useful power density was achieved; the maximum power density was 355 mW cm−2 at 700 °C. For comparison, cells were also tested with hydrogen as the fuel and CO2-free air as the oxidant at 700 °C, where the power density was about 371 or 324 mW cm−2. The performance of the cells tested under various conditions implied that ammonia might be a good fuel for a SOFC.