The truncated perturbed chain-polar statistical associating fluid theory (tPC-PSAFT) is re-parametrized for imidazolium-based ionic liquids (ILs) by fitting IL density data over a wide temperature range and restricting the model to predict very low vapor pressure values, in agreement with recent experimental evidence. The new set of parameters is used for the correlation of carbon dioxide solubility in various ILs using a binary interaction parameter, k(ij). The correlated k(ij) values are much lower than the values used previously for the same mixtures (Kroon et al., J. Phys. Chem. B 2006, 110, 9262). Furthermore, the solubilities of carbon monoxide, oxygen, and trifluoromethane in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim(+)][PF6(-)]) Are correlated. In all cases, the agreement between tPC-PSAFT correlation and experimental data for mixtures is very good.