Hildebrand solubility parameters (delta) of a series of linear low-density polyethylenes (LLDPE) were measured at several elevated temperatures by the inverse gas chromatography (IGC) method of DiPaola-Baranyi and Guillet [Macromolecules 1978,11, 228-235] With the incorporation of a compressible regular solution model, recently proposed by Ruzette and Mayes [Macromolecules 2001, 34, 1894-1907], for data analysis. It was found that, with the inclusion of the pressure-volume-temperature (PVT) properties of the pure components in the data analysis, the measured delta agreed well with those obtained from PVT measurements on similar systems. This suggests that the model of Ruzette and Mayes, even though it is mathematically less sophisticated than the conventional equation-of-state (EOS) theories, it is useful for deriving solubility properties of polymers. The results were consistent with the prediction of conventional EOS theories that, in addition to the type and strength of intermolecular interaction, PVT properties of the individual components comprising polymer solutions and blends also play a significant role in determining their phase behavior, especially at elevated temperatures.