P-x data for the vapor-liquid equilibrium (VLE) of four binary systems water + levulinic acid, water + ethyl levulinate, ethanol + levulinic acid, and ethanol + ethyl levulinate were collected at 60 degrees C. Liquid-liquid equilibrium (LLE) data for ethyl levulinate + water + levulinic acid and ethyl levulinate + water + ethanol were measured at 30 degrees C. The consistency of the LLE data was confirmed using the Othmer-Tobias method. Data were regressed using ASPEN PLUS software to generate binary interaction parameters for the NRTL-HOC property method. The resulting parameters were able to successfully reproduce experimental VLE data, and were semiquantitative for reproducing experimental LLE data.