Extraction of rhenium into the ionic liquids phase from aqueous solutions was investigated using N235 as extractant. At temperatures from 293.15 to 318.15 K, the equilibrium molalities of ReO4- were measured at an ionic strength from 0.2 to 2.0 mol.kg(-1) in the aqueous phase containing NH4Cl as supporting electrolyte. The standard extraction constants K-0 at various temperatures were obtained by methods of the Pitzer polynomial approximation. Thermodynamic properties for the extraction process were calculated.