Powder Mixed Electrical Discharge Machining (PMEDM) is considered as one of the viable methods to machine the materials which are hard and tough but with appreciable thermo-electrical properties. In PMEDM, it has been established that machinability is enhanced by adding additives in the form of fine powders in the spark gap of EDM process. In this investigation, the role of the thermo-electrical properties of workpiece on PMEDM process has been studied. Materials with distinct thermoelectric property, namely Mild Steel and Aluminium are taken as workpiece with Alumina as additive powder for the PMEDM process. Experiments have been conducted with Taguchi L9 Orthogonal Array (OA) with Material Removal Rate (MRR) and Tool Wear Index (TWI) as responses. Gap current, duty cycle and flow rate of powder mixed dielectric liquid have been taken as process parameters at 3 levels with circular copper rod of 12 mm diameter as tool electrode. Determination of the influence of properties of the workpiece on the machinability has been performed using a custom made PMEDM set-up. ANOVA and main effect plot of data means for the aforementioned conditions have been analysed. The results are noteworthy with significant influence of the properties of the workpiece on the machinability of PMEDM process. © 2019 Faculty of Mechanical Engineering, Belgrade.