When a mixture of rare earths, thorium, and uranium at pH 1.0 in sulfate medium is passed through a column (1.5 × 12 cm) of Dowex A-1(H+), rare earths pass through. Then thorium is eluted with 6Nhydrochloric acid and subsequently the uranium with 2Nnitric acid. When the mixture at pH 2.0 in nitrate medium and in the presence of 1,10-phenanthroline is fed to a column of ZeoKarb 226(H+), the rare earths pass through. Then thorium is eluted with 0.05MEDTA at pH 4.5 and subsequently the uranium with 2Nhydrochloric acid. These separation schemes are successfully applied to the analysis of monazite samples.