Isobaric vapor-liquid equilibria for the binary systems 1-propanol + water, 1-propanol + 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][triflate]), and water + [emim][triflate] as well as the vapor-liquid equilibria for the 1-propanol + water + [emim] [triflate] ternary system have been obtained at 100 kPa using a recirculating still. Electrolyte NRTL fitting parameters for the 1-propanol + water and water + [emim][triflate] systems were calculated. The measured ternary data were correlated using Mock's electrolyte NRTL model which reproduces reasonably well the experimental values. The results show that the addition of [emim][triflate] to 1-propanol + water produced an important salting-out effect, and the model predicts that at 100 kPa the azeotrope disappears when the mole fraction of ionic liquid in the liquid phase is greater than 0.34.