The UNIQUAC equation was used for calculation of vapor liquid equilibrium (VLE) as well as excess enthalpy (h(E)). Four sets of binary interaction parameters were applied: first, parameters estimated only from VLE data, then parameters from h(E) data for both the original UNIQUAC equation and the Anderson modification, and finally parameters estimated from h(E) and VLE data simultaneously. Calculations were performed for seven binary systems with polar components, representing different h(E) behavior. The cross-prediction of h(E) from VLE data works better than the reversed prediction. The model with parameters estimated simultaneously to both kinds of data can be applied successfully to both kinds of calculations, but it is a compromise between the models estimated from one kind of data.