The preparation of cadmium hexacyanocobaltate (III), CdHCC, is discussed. The product has been prepared by reacting cadmium nitrate and potassium hexacyanocobaltate (III) in a volume ratio of 2:1. The effect of the monovalent cations, H+, Na+, K+, and NH4+on the percentage retention and of pH on the loading capacity of CdHCC for cesium have been investigated. It has been found that the equilibrium behavior and the loading capacity of CdHCC after being soaked overnight in M NaCl are significantly improved. A loading capacities of 10, 30, and 60 g Cs/kg CdHCC have been achieved from simulated PWR waste, MAW and solutions of pH 12, respectively. A comparison of the distribution coefficients for cesium in different media is made.