Experimental isothermal P-x-y data for the binary systems (tert-amylmethyl ether (TAME) + the hydrocarbons n-heptane, cyclohexane, benzene and 1-hexene) and the ternary system (tert-amylmethyl ether (TAME) + 1-hexene + cyclohexane) at 313.15 K are reported. 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 both the binary and the ternary systems presented here and they have been used for predicting the behaviour of the other ternary systems involving TAME + hydrocarbon + hydrocarbon, where the four types of substitution hydrocarbons have been used.