Abstract: A process is provided whereby carbon oxides and hydrogen in a gaseous mixture that also contains hydrocarbons are caused to react over a catalyst with the production of methane in such manner that any ethane present in the reactants is virtually unaffected by the methanation reactions.The catalyst may comprise nickel or colbalt associated with alumina, silica, magnesia, chromia or urania, or mixtures thereof.The process may be operated, in relation to the catalyst, within a range of temperatures and pressures such that hydrogenation of the carbon oxides present in the gas is substantially completed at an upper temperature limit while ethane present in the gas remains substantially unreacted at the said upper limit.