A chromatographic method, namely, mass spectrometric tracer pulse chromatography, MSTPC, was used to measure the solubility of carbon dioxide in PMMA, poly(methyl methacrylate), over a wide range of temperatures (-10 to 180 degrees C) and pressures (<90 atm). In this range of experimental conditions, CO2 was present as a gas or supercritical fluid and the polymer was either in a glassy or rubbery state (T-g = 100-110 degrees C). Three lattice theories were evaluated for correlation with the experimental solubility data. The Sanchez-Lacombe, Panayiotou-Vera, and Martire-Boehm models were used to calculate the densities of the pure gas and binary liquid phases from an equation of state and the chemical potential of CO2 in both the pure gas and polymer mixtures. The solubility of CO2 in PMMA as a function of temperature and pressure was calculated from these three lattice theory models and compared with the experimental data. Only one temperature-dependent adjustable parameter was used in these calculations to fit the theoretical models to the experimental data.