With the development of new branches of industry like optoelectronics, power metallurgy, and modern techniques of raw material or plastics admixture, there is greater demand for rare earth elements of high purity. This paper presents the selective separation of neodymium(III) microquantities from samarium(III) macroquantities in the 90% v/v polar organic solvent-10% v/v 1 or 7 M HNO3 system on strongly basic anion exchangers of various types. Weight and bed distribution coefficients as well as the number of theoretical plates were determined. It is shown that the neodymium(III) content in purified samarium(III) decreases to a value below 10(-3)% under optimal conditions.