The study of liquid-liquid extraction of Cu(II) ion was carried out by using a series of hydrophobic ionic liquids; 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mimPF(6)]), 1-hexyl-3-methylimidazolium hexafluorophospahate ([C(6)mimPF(6)]), 1-butyl-3-methylimidazolium bistrifluoromethylsulfonyl imide ([C(4)mimNTf(2)]) and 1-hexyl-3-methylimidazolium bistrifluoromethylsulfonyl imide ([C(6)mimNTf(2)]) as extraction phase. Cu(II) prefer to extract into [C(4)mimPF(6)] which is the less hydrophobic of ionic liquids. The extraction behavior of Cu(II) ion depends on the type of counterion and the extraction of Cu(II) ion in ionic liquid system proceeds via similar mechanism with a molecular organic solvent. From these results, it was proposed that the extraction of Cu complexes from chloride medium proceeds through ion pair mechanism.