AbstractThe separation of uranium from thorium by anion exchange resin Amberlite IRA‐400 in ethylenediaminetetraacetate (E. D. T. A.) form was studied. After these two elements were adsorped by the resin in E.D.T.A. form, it was found that thorium could be easily desorbed with dilute solution of ferric acetate but uranium was stable toward this solution. Uranium could be only desorbed with 0.02 N of hydrochloric acid after. it was washed throughly with distilled water. These results were quite contrary to those obtained in aqueous solution by Cobell(1), who reported that the complex formed by uranium with E.D.T.A. was weaker than those of thorium. Advantage was taken of the stronger adsorption of uranium by resins in E.D.T.A. form for the separation of these two elements with quite satisfactory result