In this work, vapour-liquid equilibria for the quaternary reactive system ethyl acetate + ethanol + water + acetic acid and constituent binary systems ethyl acetate + ethanol, ethyl acetate + acetic acid and water + acetic acid has been determined at 101. 3 kPa. UNIQUAC equation was used to correlate the experimental phase equilibrium data of the quaternary system. Experimental binary data were correlated using Wilson, NRTL and UNIQUAC equations. (c) 2005 Elsevier B.V. All rights reserved.