The partition coefficients (P) of benzene and its various derivatives between hydrophobic ionic liquids and water were determined at 298.2 K. The ionic liquids used are 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([BuMeIm][NTf(2)]), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide ([BuMePyrr][NTf(2)]), and 1-butyl-3-methylimidazolium hexafluorophosphate ([BuMeIm][PF(6)]). For a given solute, the P value in the [BuMePyrr][NTf(2)]/water system is nearly equal to that in the [BuMeIm][NTf(2)]/water system. The P values of the alkylated benzenes and the chlorinated ones are slightly smaller in the [BuMeIm][PF(6)]/water system than in the [BuMePyrr][NTf(2)]/water system, whereas for the derivatives having polar substituents the P values in both the systems are comparable to each other. As compared to 1-octanol, all of the ionic liquids exhibit a higher extraction ability for aniline, benzonitrile, acetophenone, nitrobenzene, and anisole and a lower one for benzoic acid, phenol, and benzyl alcohol. The P values were analyzed by using the regular solution theory, and the contributions of solubility parameters, molar volumes, and solute-solvent specific interactions were evaluated. Each ionic liquid exhibits both the donor and the acceptor properties in the interaction with the polar substituents; the strength of the interaction decreases in the following substituent sequence: -COOH >= -OH > -OH (aliphatic) > -NH(2) > -CN > -COCH(3) >= -NO(2) > -OCH(3) > -Cl.