The modified group-contribution lattice-fluid equation of state (GCLF-EOS) was applied to predict liquid-liquid equilibria (LLE) in polymer solutions. The modified GCLF-EOS is a group-contribution form of the equation of state by Panayiotou and Vera based on the lattice-hole theory. Group contributions for the interaction energy and reference volume were developed based only on the saturated vapor pressures and liquid densities of low-molecular-weight compounds. For a mixture, group contributions for the binary interaction parameter were developed from the binary vapor - liquid equilibria of low-molecular-weight compounds. This modified GCLF - EOS model can be applied to predict LLE behavior in polymer solutions with the same group-contribution parameters as used for predicting the vapor-liquid equilibria. The only input required for the model is the structure of the molecules in terms of their functional groups.