The reaction of iron carbide with steam was examined under constant temperatures and a constant heating rate using a temperature-programmed thermogravimetry-GC/MS. Coproduction of pure Fe and H-2 from iron carbide coincides with reduction of Fe3O4 and subsequent oxidation of produced Fe by steam which formed FeO. A carbon conversion of 94% and an Fe yield of 80% were achieved, providing rapid heating and low steam concentration (10%).