Abstract The presented work describes a process for producing a mixed-conducting SOFC cermet anode through the in situ reduction of a ternary oxide. A porous nickel tungstenate (NiWO 4 ) was screen-printed and bonded onto an yttrium-stabilized zirconia (YSZ) electrolyte-supported SOFC by treatment at 1000 °C for 1 h. An (La,Sr)MnO 3 /Ce 0.9 Gd 0.1 O 2 (LSM/GDC) was utilized as the cathode with the NiWO4 acting as the anode for the SOFC. The ∼1-cm diameter fuel cell with a ∼100-μm thick YSZ electrolyte was tested in H 2 fuel at 800 °C. During the insertion of the H 2 fuel, the NiWO 4 was reduced to form a Ni/WO x cermet composite that consisted of a fine mixture of Ni-nanoparticles dispersed over the porous WO x support structure. A maximum power density of ∼104 mW cm −2 was attained for the reduced NiWO 4 anode, even with an un-optimized and dense microstructure, on an electrolyte-supported cell. The power density was increased to ∼165 mW cm −2 with the incorporation of GDC powder into the NiWO 4 anode. The same NiWO 4 /GDC composite was tested within a fuel stream of H 2 containing 10 ppm PH 3 . The cell's degradation rate was 0.006 V h −1 for 5 h at 750 °C, which is similar to that observed for conventional Ni/YSZ cermets.