The vapor pressures of lithium halide solutions in ethanol have been determined in the range of concentration from (0.01 to 2.0) mol (.) kg(-1) at 298.15 K. The activity of solvent was obtained directly and the osmotic coefficients of solutions were then calculated. An accurate reference osmotic coefficient (phi(0)) was obtained in a more diluted solution at a reference molality, m(0) (=10(-3) kg (.) mol(-1)). The ionic activity coefficient, the excess, and the change in partial molal free energy of solutions were calculated by using Gibbs-Duhem equation. The values of osmotic coefficient that obtained in this work were fitted to MSA-NRTL and Pitzer's models and the values of characteristic adjustable parameters were calculated. It is shown that the goodness and the overall quality of the fit for both models are excellent. (C) 2003 Elsevier Ltd. All rights reserved.