In the present work, Electrical Discharge Machining (EDM)) was employed to machine EN-31 (AISI 52100) tool steel with copper electrode by adopting response surface methodology. To study the process performance of material removal rate( Volume of material removed per minute) and surface roughness (average roughness of machined surface Ra), variables such as Pulse on time, duty cycle, peak current and concentration of the aluminium oxide powder were added into the kerosene dielectric liquid of a die-sinking electrical discharge machine. Analysis of variance (ANOVA) has been applied to investigate the influence of process parameters and their interactions. Suitable mathematical model has been formulated in order to estimate the machining characteristics. Finally the parameters were optimized for maximizing MRR and minimizing SR using desirability function approach. The recommended optimal process conditions have been verified by conducting confirmation experiments.