We report miscibility behavior for synthetic biodegradable aliphatic polyester (BDP) and poly(vinyl acetate) (PVAc) blends by investigating their thermal, rheological, and mechanical properties. Two Separate glass transition temperature peaks for the BDP/PVAc blends proved that these blend systems are immiscible. From the rheological measurement, the shear viscosity as a function of shear rate is observed to increase with increasing PVAc content in BDP/PVAc blends, since PVAc has a relatively high molecular weight compared to BDP. Moreover, BDP blends with 10 wt % PVAc have excellent mechanical properties.