Abstract: Hydrogen-containing gas mixtures including saturated and unsaturated hydrocarbon gases, carbon monoxide and organic sulfur contaminants are purified by passing them over a hydrogenation catalyst containing phosphorus with the addition of predetermined limited amounts of water. The process makes it possible to produce hydrogen-containing gases which can be used for hydrogenation processes with the elimination or reduction of carbon monoxide, olefins and organic sulfur, all brought about simultaneously by passing the gas mixture over the same catalyst and in the same reactor.