Experiments were performed to obtain basic data on cesium ion removal characteristics of metal hexacyanoferrate (II) impregnated zeolite. The cesium ion was present in liquid wastes also containing sodium salts. The effects of impregnated ion that forms hexacyanoferrate, the amount of ion, sodium sulfate concentration, pH, and co-existing ions were studied. The results of column experiments showed the removal efficiency of copper hexacyanoferrate (II) impregnated zeolite was sufficiently satisfactory for use in an ion exchange column. Excellent performance was obtained for sodium sulfate concentrations of 0 to 15 wt% and a pH of 1.5 to 10.