Liquid-liquid equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 3-hydroxy-2-butanone + butyl ethanoate) at (298.15, 308.15, and 318.15) K and 101.3 kPa. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using the Othmer-Tobias correlation. The LLE data of the ternary systems have been predicted by UNIFAC methods.