Effects of CeO 2 additive to Fe-based mixed oxide mediums with Rh and ZrO 2 for chemical hydrogen storage were investigated in terms of stability and reactivity of the mediums in water splitting oxidation with repeated redox cycles. The mediums with CeO 2 content ranging from 0 to 30wt% were prepared by co-precipitation method using urea solution as a precipitant. The hydrogen storage and release properties were investigated during repeated isothermal redox cycles at 823K for reduction with hydrogen and 623K for oxidation with water vapor under atmospheric pressure. The amount of hydrogen produced by the mediums, both with and without CeO 2 , was maintained at an almost constant level over ten repeated redox cycles. However, the oxidation rates of the mediums without CeO 2 were decreased during repeated redox cycles while that increased with increasing CeO 2 contents. Especially, the mediums added with 30wt% of CeO 2 (FRZC-30) showed high activity and stability for ten redox cycles, the degree of hydrogen storage was almost maintained ca. 1.9wt% on the basis of total amount of the medium.