Thermodynamic modelling of the pressure/temperature conditions for the Franklin Metamorphic Complex, located in central Tasmania, and the Port Davey Metamorphic Complex, located on the south west coast of Tasmania, reveals marked contrast in the metamorphic histories of the two complexes.Garnet-core isopleth thermobarometery for both the Franklin and Port Davey Metamorphic Complexes yielded very similar results (~ 600o C, 6,000 bars) for the formation of the garnet cores in the pelitic schists from these two regions. However, their metamorphic history subsequent to their early stage of garnet growth is very different. Garnet rims and matrix minerals from samples from the Port Davey Metamorphic Complex record a temperature (~ 650o C at 6,000 bars) for their formation which is only slightly higher temperature than was obtained for the formation of the garnet cores. The Franklin Metamorphic Complex, on the other hand, appears to have maintained nearly isothermal conditions whilst undergoing a rapid increase in pressure; garnet rims and matrix minerals. the metapelites in this complex record conditions of ~700o C, 14,000 bars. These pelitic schists record a near isothermal compression event with no evidence of the retrograde path retained in the samples, indicating exhumation at plate tectonic rates.