The extraction behavior of lanthanides from aqueous solutions into an ionic liquid (IL) was investigated with N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) as a ligand. The extraction performance of TPEN for lanthanides is greatly enhanced by dissolution in IL compared to in chloroform. Furthermore, the stripping of lanthanides from IL into a receiving phase is successfully achieved under acidic conditions.