The catalytic production of syngas from methane was investigated over alumina- and silica-supported ruthenium catalysts. It is shown that the support is involved in reactions with reactants and products somewhat modifying the catalytic behaviour. From isotopic tracing experiments it is concluded that the syngas production reaction follows the same indirect pathway over the two catalysts, i.e. the sequence of total oxidation of methane, followed by reforming of the unconverted methane with carbon dioxide and steam to syngas. Recent literature is analysed in the light of our results.