The understanding of the polymer + solvent interactions is of fundamental importance in the development of new products and processes in several important industrial sectors, such as special paints, cosmetics, packing, manufacture of polymeric membranes, etc. Although the nature of these physical interactions is well known, the thermodynamic modeling of polymer + solvent systems in industrial applications presents difficulties, mainly due to the necessity to characterize not only the polymeric phase, in terms of properties that are easily measurable, but also the interaction of the polymer with the other components of low molar mass, through conveniently chosen parameters. In this work, the perturbed chain-statistical associating fluid theory (PC-SAFT) and Sanchez-Lacombe (SL) equations of state (EoS) are used in order to model the gas solubilities of binary systems composed by polystyrene and chlorofluorocarbons, hydrochlorofluorocarbons hydrofluorocarbons and supercritical fluids, which experimental data were obtained from the literature. The results were compared with those obtained by the traditional Peng-Robinson (PR) EoS. In each thermodynamic model, a one fluid-type van der Waals (vDW) mixing rule with conventional combination rules and a temperature-dependent binary interaction parameter were used. Solubilities correlated by the PC-SAFT EoS are in good agreement with the experimental data when compared with those obtained with the SL and PR EoS. (C) 2007 Elsevier B.V. All rights reserved.