In the present communication, we report the studies concerning liquid-liquid-solid equilibria for the ternary system sodium thiosulphate (Na2S2O3) + ethanol + water at ambient pressure and at room temperature (303 +/- 2 K). The solubility data of Na2S2O3 are reported for solutions in water, ethanol and solutions of varying concentrations of ethanol in water. The phase diagram for the said system is developed, described and compared with similar system K2CO3 +methanol+ water. These results have been explained in terms of structural properties of aqueous ethanol solutions and further discussed in terms of the effect of ions to cause phase separation. (c) 2007 Elsevier B.V. All rights reserved.