In this work, the carbon dioxide solubility onionic liquids was calculated using two models:The first model, which employs the Setchenow’scoefficients, depends on gas and ions into water.The second model is based on Duan y Sun datafitting. Aqueous water containing NaCl and KClwas used to calculate the carbon dioxide solubility,via the first model. On the other hand, the carbondioxide solubility into MgCl2 and Na2SO4 solutionswas calculated using the second model. Theresults indicated that the carbon dioxide solubilitydecreased when the salts concentration increased.