The tracer level separation of rare earth elements has been achieved by using a small column (3 mm i.d. × 140 mm height) of Kel-F powder (polytrichlorofluoroethylene) loaded with di(2-ethylhexyl)orthophosphoric acid (HDEHP). Suitable column preparation procedure has been determined by investigating the EuTb separation. The column was operated at 85 ± 1°C and elution was carried out with a solution of hydrochloric acid having the proper concentration. For the resolution of mixtures containing more than two lanthanide elements the gradient elution method was used. The following separations are reported: EuTb, EuGdTbSm, LaCePrNdPmSmEu, LaPrSmEuGdTbDyHoErTmYbLu, TbYb.