The solubility of ethane gas has been measured in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide within a temperature and pressure range of (290 to 370) K and (0.4 to 13) MPa. The results have shown high ethane solubility in this ionic liquid, but lower than the corresponding solubilities of carbon dioxide in the same ionic liquid. For example, the solubility of ethane at 313 K and 4 MPa is in the range of 0.3 mol fraction while that of CO(2) is in the range of 0.5 mol fraction. The gas solubilities increase with pressure and decrease with temperature. The pressure-temperature relationship is seen to be linear for any particular isopleth. However, the pressure-composition solubility isotherms show a highly curved behavior in which the solubility increases considerably with pressure up to a certain ethane concentration, above which further pressure increase has little effect on the ethane solubility.