This paper presents the results of a study on three-objective optimization when powder-mixing discharge machining (PMEDM) of SKD11 tool steel cylindrical parts. Three single-objective functions were selected for this problem. They are the minimum surface roughness (SR), the maximum material removal speed (MRS), and the minimum electrode wear rate (EWR). Besides, six main input parameters including the powder concentration, the powder size, the pulse on time, the pulse off time, the servo current, and the servo voltage were inves-tigated. In addition, the Taguchi method and Gray Relational Analysis (GRA) were used to design and analyze the experimental results. Finally, optimal input parameters to achieve the minimum SR, the maximum MRS, and the minimum EWR simultaneously have been suggested.