This research focused on a study of the ionic liquid 4-methyl-N-butylpyridinium tetrafluoroborate ([mebupy]-BF(4)) as a solvent in liquid-liquid extraction. Liquid-liquid equilibrium data were obtained for mixtures of 4-methyl-N-butylpyridinium tetrafluoroborate + (benzene or ethylbenzene or m-xylene) + (N-hexane or N-octane) at T = (313.2 and 348.2) K and T = (313.2 and 333.2) K for the ternary mixture with benzene and p = 0.1 MPa. The experimental data for the binary and ternary systems were well-correlated with the NRTL model. The aromatic/aliphatic selectivity values were comparable to those of toluene + N-heptane. The ionic liquid [mebupy] BF(4) is therefore a suitable solvent for an industrial extraction process for the separation of aromatic and aliphatic hydrocarbons.