Because of its low cost and availability, Thermoplastic Starch (TPS) has become an important feedstock in bioplastics. This study focuses on blends of potato starch-based TPS with Low Density Polyethylene (LDPE) and the morphology development of such blends around the phase inversion point. The effect of glycerol and water content on TPS rheology and the subsequent morphology development with LDPE of various viscosity levels has been investigated. Blends have been mixed in one-step using a twin-screw compounder and extruded into strands. The investigated compositions included plasticizer levels of 30 to 40 wt% glycerol and 0 to 10 wt% water based on the TPS phase and of TPS fractions in LDPE ranging from 40 to 80 wt%. The TPS/LDPE viscosity ratio was modified either by increasing the TPS plasticization or by proper selection the LDPE grade. Morphology assessment was carried out by Scanning Electron Microscopy on microtomed surfaces after the TPS phase had been extracted by acid etching in order to increase the contrast. For formulations where TPS formed the matrix, Energy Dispersive Spectroscopy has been coupled with SEM to identify components. Rheology measurements were carried out on pure TPS and on TPE/LDPE blends using capillary rheometry. Particular attention was given to the effect of TPS humidity on viscosity and therefore humidity levels were carefully measured by Karl Fisher titration prior to rheometry. Different types of blend morphologies were achieved from droplets to co-continuity and the relation between the phase transitions and the viscosity ratio was established.