The optimum conditions for extraction chromatography using 2ethyl-hexyl 2-ethylhexylphosphonate resin to separate thulium, yetterbium and luticium were studied. According to the proposed procedure, several grams of yetterbium oxide (purity = 99.95%) and luticium oxide (purity = 99.90%) were separated from the mixed heavy rare earth oxides on laboratory scale. Their relatively high recoveries (99% and 95% for Yb2O3 and Lu2O3 respectively) may be satisfactory