A static apparatus was installed for measuring isothermal vapor-liquid equilibrium (VLE) data for the binary and ternary mixtures composed of ethanol, acetone, and diisopropyl ether in a temperature range of 343-363 K. Maximum pressure azeotropes appeared in the binary systems containing diisopropyl ether. All the binary data passed the point, area, and infinite dilution thermodynamic consistency tests. Furthermore, the Wilson, NRTL and UNIQUAC models correlated the binary data well. The UNIQUAC model yielded the best prediction for the ternary system.