Liquid-liquid equilibrium (LLE) data for the ternary systems of (water + formic acid + ethyl heptanoate) and (water + acetic acid + ethyl heptanoate) were investigated at 288.15, 298.15, and 308.15 K and atmospheric pressure. The tie-line data was determined experimentally for each temperature. The experimental data was compared with the results predicted by the UNIFAC method, and correlated by means of UNIQUAC model. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. Distribution coefficients and separation factor values were evaluated for the immiscibility region. (C) 2013 Elsevier B.V. All rights reserved.