A process for producing 1,1,1,2-tetrafluoroethane, which comprises reacting 2,2-dichloro-1,1,1,2-tetrafluoroethane, 2-chloro-1,1,1,2-tetrafluoroethane or a mixture thereof with hydrogen in the presence of a hydrogenation catalyst consisting essentially of a Group VIII element as the main component and at least one element selected from the group consisting of Group IB elements, lanthanum and lanthanide elements, as an additional component.