Abstract Supported ternary alloy catalysts of iron, cobalt, and nickel for carbon monoxide hydrogenation were studied systematically. Alloying of these metal components mostly enhanced the catalytic activity and suppressed methanation. The alloy catalyst of 50Co50Ni yielded a large amount of gasoline compounds; and the cobalt-rich iron-cobalt system was selective for olefin formation. The increase in iron content lowered the overall catalytic activity and accelerated methanation. The affinities of the metal surfaces to hydrogen and carbon monoxide adsorption appear to be affected by alloying, resulting in a change in the ratio of active hydrogen to carbon monoxide on the surface. The catalytic activity of supported iron-cobalt-nickel ternary alloy catalyst was largely determined by the amount of active hydrogen.