Abstract: In this study the optimization of the Electrical Discharge Machining (EDM) process with multiple performance characteristics based on orthogonal array with the Grey relational analysis was studied. The Grey relational analysis theory was used to resolve the complicated interrelationships among the multiple performance characteristics. In the present study, attempt was made to find the optimal machining conditions under which a blind-hole can be drilled using a multihole electrode. The Taguchi method was used to determine the relations between machining parameters and process characteristics. In this study, the machining parameters, namely electrode polarity, discharge current, pulse on time, pulse off time and dielectric pressure were optimized with considerations of multiple performance characteristics including machining time, electrode wear and surface roughness. Experimental results showed that machining performance in the EDM process can be improved effectively through this approach.