In this study, machining performance ouput parameters such as machined surface roughness (SR), material removal rate (MRR), tool wear rate (TWR), were experimentally examined and analyzed with the diversifying and changing machining parameters in (EDM). The processing parameters (input par.) of this research are stated as tool material, peak current (I), pulse duration (t(on)) and pulse interval (t(off)). The experimental machinings were put into practice by using Hadfield steel workpiece (prismatic) and cylindrical graphite electrodes with kerosene dielectric at different machining current, polarity and pulse time settings. The experiments have shown that the type of tool material, polarity (direct polarity forms higher MRR, SR and TWR), current (high current lowers TWR and enhances MRR, TWR) and pulse on time (t(on)=48 square s is critical threshold value for MRR and TWR) were influential on machining performance in electrical discharge machining.