The solubilities of 1-ethyl-3-methylimidazolium hexafluorophosphate, [emim][PF6], in aromatic hydrocarbons (benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene) and of 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim] [PF6], in the same aromatic hydrocarbons, in n-alkanes (pentane, hexane, heptane, octane), and in cyclohydrocarbons (cyclopentane, cyclohexane) have been measured by a dynamic method from 290 K to the melting point of the ionic liquid or to the boiling point of the solvent. The melting point, enthalpy of fusion, and enthalpies of solid-solid phase transitions were determined by differential scanning calorimetry (DSC). The solubilities of [emim] [PF6] and [bmim] [PF6] in aromatic hydrocarbons decrease with an increase of the molecular weight of the solvent. The differences of the solubilities in o-, m-, and p-xylene are not significant. The intermolecular solute-solvent interactions are very small. The liquidus curves were correlated by means of the UNIQUAC and NRTL equations, utilizing parameters derived from the solid-liquid equilibrium. The average root-mean-square deviation of the solubility temperatures for all solvents was 0.41 K and depended on the particular equation used.