This paper introduces the results of research on optimization of powder mixture electrical discharge machining (PMEDM) process when processing cylindrically shaped parts with graphite electrodes. In this study, 90CrSi tool steel was chosen as the workpiece material. Besides, the electrode wear rate (EWR) is selected as the objective function of the optimization problem. To solve this problem, an experiment with the Taguchi design was performed. Also, the Minitab R19 software was used to design experiments and analyze the results. The influence of the input process parameters, including the powder concentration, the pulse on time, the pulse off time, the servo current, and the servo voltage on EWR was investigated. In addition, optimal process parameters for minimum EWR were given.