The principle and measuring technique for determining the thermal diffusivity of aqueous solutions of sodium chloride using the laser-induced thermal grating technique are described. Experimental thermal diffusivity data are presented for aqueous solutions of sodium chloride in the temperature range of 290 to 373 K and concentration range of 0 to 4 mol/kg. The results converted to thermal conductivity appear good agreement with the experimental data in the literature. On the basis of the experimental thermal diffusivity data, an empirical correlation for calculating the thermal diffusivity of aqueous solutions of sodium chloride is given.