The solubility coefficients of a wide range of gases in polyethylene were calculated with a recently developed integral equation theory of gas solubility. Standard Lennard-Jones potential interactions were used for united atom models of both gas molecules and polyethylene, CH2, sites. The cross interactions were assumed to be given by the standard Bertholet relationships, and care was taken to stay within the Henry＇s law limit. The predictions of the theory for the solubility of low critical temperature gases in polyethylene were compared to the experimental values. The agreement was excellent, and for the cases considered, there was no justification for introducing non-Bertholet cross interactions. On the other hand, the results were found to be sensitive to the details of the CH2-CH2 interaction.