The equilibrium solubility of sodium 1-naphthalenesulfonate in binary NaCl + water, Na2SO4 + water, and C2H5OH + water solvent Mixtures Was measured by a steady-state method at elevated temperatures from (278.15 to 323.15) K. The results of these data were correlated by a modified Apelblat equation. The dissolution enthalpy (Delta H-d) and entropy (Delta S-d) of sodium 1-naphthalenesulfonate in solutions of different mole fraction were obtained.