The autothermal reforming of methane to syngas for use in the Fischer-Tropsch synthesis was studied in this work over PdO containing various combinations of CeO2, BaO or SrO in a washcoated form on a metallic monolith at atmospheric pressure. This study focused on the autothermal operation of the system, in which an electric heater inside the reactor was used only to reach the ignition temperature, and thereafter the autothermal reaction successfully sustained itself without any external heat source. It was concluded from the experiments that the PdO/Al2O3 catalyst was better than the others, except for PdO-CeO2-BaO-SrO/Al2O3, which showed similar performance in terms of the CH4 conversion and H2+CO selectivity, while affording a higher H2/CO ratio (close to ca. 3) than the PdO/Al2O3 catalyst did (close to ca. 2). The gas hourly space velocity and O2/CH4 ratio governed the methane conversion, while the H2O/ CH4 ratio controlled the H2/CO ratio. A methane conversion of ~87%, H2+CO selectivity of ~94%, H2/CO ratio of ≤2.9, and M factor .2.15 were obtained under the conditions of a gas hourly space velocity (GHSV) of 120,000 h-1, O2/CH4=0.6 and H2O/CH4=0.5.