Solubility data of the NaCl+LiCl+H 2 O system have been measured at 15 ∘ C. These data along with others recorded in the literature, at 25, 50, and 100 ∘ C, have been correlated using the Pitzer model and the extended Debye–Hückel model. The latter was used to determine the activity and osmotic coefficients of the binary systems NaCl+H 2 O and LiCl+H 2 O. The results obtained in this work show that the calculated solubility values are in good agreement with the experimental ones.