Critical temperature (T-c) and critical pressure (p(c)) of the ternary mixture of ethylene + benzene + ethylbenzene (the mole ratio of ethylbenzene to benzene was fixed at 0.95:0.05) were measured by using a high-pressure view cell with direct visual observation. The interaction coefficients obtained from the critical properties of the relevant binary systems were used to predict the critical properties (T-c,p(c)) of the ternary mixture. The agreement between the prediction and experiments is satisfactory.