The enthalpies of solution of NaCl in water at 303.15, 308.15, and 313.15 K have been measured as a function of molality in a heat-flux calorimeter. The covered range is 0.005 to 0.12 mol·kg −1. Values for the apparent relative molar enthalpies have been used to analyse the experimental results. The enthalpies of solution at infinite dilution at 303.15, 308.15, and 313.15 K obtained are 3.32, 2.78, and 2.25 kJ·mol −1, respectively.