A model has been developed for prediction of Wilson parameters from single component properties. Activity coefficients and VLE data for miscible binary or multicomponent systems can be calculated from the standard form of the Wilson equation using these properties. The major advantage of this model is that experimental determinations of binary data are not required. Relevant properties for a fairly large number of chemical species have been provided. This method has been compared with UNIFAC, which is generally used for prediction of activity coefficients and has been found to give comparable results with considerably less computational effort. Copyright © 1985 American Institute of Chemical Engineers