Pressure-Volume-Temperature (PVT) behavior of three biodegradable polymers, Polylactide, poly(butylene succinate), and poly(butylene succinate-co-adipate), was measured at temperatures from 313 to 493 K and pressures up to 200 MPa. The PVT data in molten state were compared with predicted values of a group contribution modified cell model equation of state (GCMCM EOS). It was found that the GCMCM EOS coupled with one specific volume datum at atmospheric pressure could predict the PVT of the polymer melts to within 0.46% in an average relative deviation of specific volume.