Direct internal reforming of hydrocarbon fuels such as gasoline and diesel has been problematic due to coking on Ni-based SOFC anodes. This paper describes stable direct internal reforming SOFCs (Ni-YSZ/YSZ/LSM-YSZ) using anode reforming catalysts. Button cells were tested with a separate catalyst piece placed against the anode. Button cell power densities of ∼0.5W/cm 2 at ∼800°C have been demonstrated with n-dodecane and n-tridecane mixed with H2O-CO2-air. Life tests with n-dodecane showed stable operation for > 140 h. Flattened-tube segmented-in-series modules with 14 cells on each side were tested with a catalyst layer coating on the fuel side of the zirconia support tube. For iso-octane mixed with either air or H2O-CO2-air, a stable maximum power density of ∼ 0.6W/cm2 was obtained at ∼ 800°C.