A scheme has been developed using the group contribution lattice-fluid equation of state (GCLF-EOS) to predict the pressure-volume-temperature (PVT) behavior of polymers in the amorphous state. The model requires only the structure of the molecule as input information. Prediction results with an average error of 2% have been obtained for a wide variety of polymers. A table of 23 different group contributions is presented. With this set of group parameters, the GCLF-EOS can be applied in the prediction of equation of state properties of a wide variety of homopolymers, random copolymers, and polymer blends.