Isothermal vapor-liquid equilibrium data at (39.5, 55.0, and 70.6) degrees C have been measured for the system acetone (1) + methanol(2) + lithium nitrate (3) at constant salt molalities (0.000, 0.500, 1.00, 2.000, and 3.000) with the help of headspace gas chromatography. The data were compared with the predicted results using the LIQUAC model.