We report gas solubilities in molten polymers for two systems : the solubility of carbon dioxide in poly(dimethylsiloxane) and the solubility of 1,1-difluoroethane in polystyrene are measured in the range of temperatures and pressures where the gas is supercritical. The solubility data are correlated by two lattice-theory-based equations of state, namely, the Sanchez-Lacombe and Panayiotou-Vera equations of state, which employ a single adjustable binary interaction parameter. Both equations of state provide satisfactory descriptions of the solubility data when the binary interaction parameter is allowed to depend on temperature. The utility of the mixture equations of state is illustrated by predictions of swollen volume, isothermal compressibility, and thermal expansion coefficient for the mixtures over the range of data.