The double-perovskite Sr 2 MgMoO 6-δ (SMMO) was investigated as an anode material of a solid oxide fuel cell. Via a synthetic method based on thermal decomposition of metal complexes with ethylenediaminetetraacetic acid as the complexant, phase-pure SMMO was readily obtained. Oxygen vacancies are introduced by reduction with 5% H 2 at 800°C. With a 300 μm thick La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 O 2.815 disk as the electrolyte and SrCo 0.8 Fe 0.2 O 3-δ as the cathode, the SMMO anode showed power densities of 0.84 W/cm 2 in H 2 and 0.44 W/cm 2 in CH 4 at 800°C. Moreover, it performed stably on power cycling and tolerated sulfur and moisture well. Only 1% degradation in the output was observed in H 2 containing 5 parts per million (ppm) H 2 S and 16% degradation in H 2 containing 50 ppm H 2 S compared with the output in pure H 2 . Thermogravimetric analysis showed a drop in mass at around 750°C in the atmospheres of both air and 5% H 2 , indicative of the formation of oxygen vacancies. The mean thermal expansion coefficient was a = 12.7 X 10 -6 K -1 at the operating temperatures. The conductivity strongly depended on the atmosphere, and the electronic activation energies were E a = 0.084 eV in H 2 and 0.126 eV in CH 4 . Our results show that SMMO is a potential anode material for operation with natural gas.