A modified procedure of using the Huron−Vidal mixing rule based on UNIFAC activity coefficients at infinite dilution (HVID) at low pressures is shown to be useful for making vapor−liquid equilibrium (VLE) predictions for polar and nonpolar systems at low and high pressures. Four cases were considered: (a) symmetric polar systems; (b) systems containing alkanols and hydrocarbons; (c) systems containing acetone and hydrocarbons; (d) hydrocarbon mixtures. Prediction of both low- and high-pressure VLE for binary systems is good. The HVID model, using UNIFAC ‘93 activity coefficients at infinite dilution, performs satisfactorily in the VLE predictions of ternary systems also.