Vapor pressure of H 2 O+NaNO 3 and H 2 O+NaNO 2 solutions were measured with static method from 298.1 to 353.1K in a range of salt mass fractions between 0.05 and 0.50. As well, the vapor pressure was determined for quaternary mixtures LiNO 3 +NaNO 3 +KNO 3 +H 2 O (salt mass ratio 53:5:42) and LiNO 3 +KNO 3 +NaNO 2 +H 2 O (salt mass ratio 53:35:12) from 313.1 to 353.1K and total salt mass fraction of 0.30, 0.40 and 0.50. The experimental vapor pressure data of binary systems were correlated with the temperature and the liquid-phase composition using an analytical polynomial equation. The capability of the electrolyte non-random two liquid model (Electrolyte-NRTL) to predict the vapor–liquid equilibrium was evaluated by comparing predicted and experimental data of the mixtures studied in this work.