Neodymium, samarium, and gadolinium were separated by a liquid- liquid chromatographic technique. Sulfuric acid was more effective than hydrochloric or nitric acid as an eluent with di(2-ethylhexyl) phosphoric acid (ehpa) as the stationary phase. Recovery of 45 percent of the neodymium as >90 percent nd2o3, 84 percent of the samarium as >99 percent sm2o3, and 50 percent of the gadolinium as >99 percent gd2o3 was achieved. The degree of separation and the time required for the separation can be varied by changing the concentration of the eluent and the number of stages in the system. A system comprising a primary amine organic extractant and an aqueous eluent containing diethylenetriaminepentaacetic acid (dtpa) was less effective for separating the rare earths.