The new equation of state proposed by Brandani et al. has been extended to mixtures, and appropriate mixing rules have been used for the parameters. Three adjustable binary parameters have been used to fit the experimental data of 13 binary mixtures containing at least one polar compound, with the exception of the system carbon dioxide-n-butane. The results of the fitting are satisfactory. When applied to a ternary mixture, predicted and experimental compositions of the liquid and vapor phase agree very well.