Experimental isothermal P-x data for the ternary system isopropyl ether + 2-butanol + benzene and for the binary systems isopropyl ether + 2-butanol and 2-butanol + benzene at T = 313.15 K are reported. A static technique consisting of an isothermal total pressure cell was used for the measurements. Data reduction by Barker's method provides correlations for G(E), using the Margules equation for the binary systems and the Wohl expansion for the ternary system. Wilson, NRTL, and UNIQUAC models have been applied successfully to binary and ternary systems. The mixtures measured exhibit positive deviation from ideal behavior. The binary system benzene + 2-butanol exhibits positive azeotropy, and no ternary azeotrope has been detected in the ternary mixture.