AISI H13 hot work tool steel is a material that is frequently used in industrial molding applications due to its mechanical and thermal properties. Electric Discharge Machining (EDM) is a preferred method especially for the machining of parts with complex geometry and high dimensional precision. In this study; the effects of machining parameters on hole diameter and surface quality were investigated experimentally when drilling hardened AISI H13 hot work tool steel using different machining parameters (current, pulse on- time, electrode material) by electric discharge machining method. The experimental design was developed with the Taguchi method, experimental parameters were determined using the L27 orthogonal array. In the experimental design; three different electrode material (Copper, Graphite, Tuncop), three different pulse-on times (200, 300, 400 µs), three different currents (4, 8, 12 A), 0.5 mm depth of cut and 50 µs pulse of time was used as machining parameters. Experimental results were evaluated by using analysis of variance (ANOVA) and signal/noise (S/N) ratio. As a result of the study, it was determined that the machining parameters have an effect on the dimensional accuracy of the hole diameter. Processing parameters that the required to obtain the hole diameter closest to the electrode diameter was determined as A3B1C1 (Copper - 200 µs - 4 A) using Signal/Noise ratios. When the ANOVA results were evaluated, it was determined that the most effective machining parameter on the dimensional accuracy of the hole diameter as the electrode material, and the least effective machining parameter was the pulse-on time.