The phase transfer catalysis reaction is gaining more and more attention in chemical industry. Usually, the chemicals used as phase transfer catalyst are organic salts. Unfortunately, the effect of an organic salt on the vapor - liquid equilibrium (VLE) of a mixture has hardly been reported in literature. In this study, the effect of the benzyltriethylammonium chloride organic salt on the VLE of ethanol-water mixture was obtained experimentally. It is observed that this organic salt can shift and even break away the azeotrope of ethanol - water mixture as an inorganic salt does. The experimental data were correlated with the models of Tan (1987, 1990) and Ohe (1991). The results were not satisfactory probably due to the complicated interactions among ions and molecules and the big different particle sizes of ion, solvent molecule, and salt molecule. The vapor pressures of benzyltriethylammonium chloride-ethanol mixtures needed in this study for determining solvent-salt interaction parameters in the correlation model were also measured and regressed by the Patil model (1990).