An aliphatic/aromatic polyester blend has been dealt with in this study. As an aliphatic polyester, poly(butylene succinate) (PBS) was used, which is thought to possess biodegradability, but it is relatively expensive. It has been blended with poly(butylene terephthalate) (PBT) in order to obtain a biodegradable blend with better mechanical properties and lower cost. The miscibilities of PBS-PBT blends were examined not only from the changes of T-g but also from log G'-log G " plots. Dynamic mechanical thermal analyzer (DMTA) was an appropriate, sensitive method to obtain the glass transitions properly. Thermal stabilities of PBS and PET were also verified at the temperature of 240 degrees C. A transesterification reaction between two polyesters at 240 degrees C was hardly detectable so that it did not affect the miscibilities and properties of the blends.