Solubilities of pure carbon dioxide and propane and those of the mixed gases carbon dioxide + nitrogen and carbon dioxide + propane in 1-hexyl3-methylimidazolium tri(bisfluoromethylsulfonyl)imide were experimentally studied at 298.15 K and up to 1 MPa. A group-contribution lattice fluid equation of state was applied for the prediction of the solubility of pure and mixed gases with ionic liquids. Predicted results were found in reasonably good agreements with experimental data. (c) 2006 Elsevier B.V. All rights reserved.