For the ternary system water + ethyl propionate + methanol, and the constituent binaries, the surface tension at 303.15 K and atmospheric pressure was measured over the whole miscible composition range. The liquid interfacial tension was determined in the liquid-liquid equilibrium range at the same conditions of temperature and pressure. Correlation of the excess surface tension of the above mentioned binary and ternary systems as well as for the ternary water + ethyl butyrate + methanol and constituent binaries, was performed with empirical and thermodynamic-based models. The interfacial tension was correlated with the equation of Fu et al. The prediction of the surface tension of the binary and ternary systems was made using the model of Sprow and Prausnitz. The models of Fu et al. and Li et al. were also applied to predict the surface tension in the ternary systems. The liquid interfacial tension of the ternary systems was correlated and predicted using the relations proposed by Li and Fu and Fu et al., respectively, with satisfactory results. (C) 2003 Elsevier B.V. All rights reserved.