A process for producing hydrogen comprising reacting at least one hydrocarbon and steam in the presence of a complex metal oxide and a steam-hydrocarbon reforming catalyst in a production step under reaction conditions sufficient to form hydrogen and a spent complex metal oxide, wherein the complex metal oxide is represented by the formula (A'.sub.xCa.sub.x'Mg.sub.x'').sub.x(B'.sub.yMn.sub.y'Fe.sub.y'').sub.yO.s- ub.n where A' represents at least one element selected from the group consisting of Sr, Ba, a Group 1 element, and an element of the Lanthanide series according to the IUPAC Periodic Table of the Elements; B' represents at least one element selected from the group consisting of Cu, Ni, Co, Cr, and V; 0.ltoreq.x.ltoreq.1, 0.ltoreq.x'.ltoreq.1, 0.ltoreq.x''.ltoreq.1 wherein x+x'+x''=x; 0.ltoreq.y.ltoreq.1, 0.ltoreq.y'.ltoreq.1, 0.ltoreq.y''.ltoreq.1 wherein y+y'+y''=y; 1.ltoreq.x.ltoreq.10; 1.ltoreq.y.ltoreq.10; and n represents a value such that the complex metal oxide is rendered electrically neutral.