Cost analysis of wire-EDMing operation was investigated in this study. Servo voltage, pulse on time, pulse off time, wire feed rate, and wire tension were varied in the experiment to define the optimal conditions for supporting wire-EDMing process. Taguchi's L27 orthogonal array was applied for designing the experiment. Machining cost, material removal rate (MRR), and surface roughness were taken into consideration as the process responses. From the experiment, increasing the servo voltage, pulse off time, and wire feed rate could reduce the surface roughness, whereas an increase in pulse on time and wire tension gave poor surface quality. Increasing servo voltage and pulse on time significantly affected the kerf width; comparing to other factors, they caused insignificant changes in the kerf width. Additionally, the correlation between machining cost and machining performance was analyzed and discussed in this study.