Partial oxidation of methane to synthesis gas was investigated in a reactor consisting of an oxygen-permeable SrFeCo 0.5 O y membrane tube and a Ni/γ-Al 2 O 3 catalyst bed located after the membrane tube. In this reactor, part of methane reacted with oxygen that permeated through the membrane from air, and the resultants (H 2 O, CO 2 ) and the rest of methane were transported to the catalyst bed where they were converted to syngas. When a reactor of membrane surface area 4.6 cm 2 was run at 900 °C with a methane feeding rate of 26.8 mL/min, the throughput conversion of methane was ∼98%, the CO selectivity ∼98%, H 2 /CO ∼1.8, syngas generation rate 16 mL/min/cm 2 . Under the reactor conditions, the layered phase Sr 4 (Fe,Co) 6 O 13 in the membrane gradually decomposed to a perovskite phase SrFe 1-x Co x O 3-δ with high oxygen permeability and spinel phase [(CoFe)] 2 CoO 4 with catalytic activity toward the oxidation of methane. The Ni-based reforming catalyst exhibited desirable activity and stability in the membrane reactor, which may be attributed to the absence of the "hot spots" in the catalyst.