A process for producing a methane-rich gas comprising the steps of: a) mixing a feed gas, comprising carbon monoxide and hydrogen, and a recycled methane-rich gas, comprising methane, to produce a gas mixture, comprising carbon monoxide, hydrogen and methane; b) reacting at least part of the carbon monoxide and hydrogen in the gas mixture in the presence of a methanation catalyst to produce a methane-rich product gas comprising methane, carbon dioxide and water; c) treating at least part of the methane-rich product gas to remove carbon dioxide to produce a methane-rich carbon dioxide-lean gas; and d) recycling at least part of the methane-rich carbon dioxide-lean gas to mixing step a) as recycled methane-rich gas.