Wire EDM is a specialized thermal machining method that uses a thin wire electrode to cut conductive materials with high precision, including complicated shapes and sharp edges. The investigation uses a CNC Wire EDM machine with a molybdenum wire electrode and an AISI 4140 steel workpiece. The aim was to achieve superior surface finish and dimensional accuracy for spur gears. Control parameters like current, Pulse on (T-on) time, and pulse off (T-off) time were chosen to experiment with the performance measure in terms of surface roughness. 9 experimental runs (L9 OA) were conducted in total, using an orthogonal array, and for the Surface Roughness, the appropriate combination of control factor levels was identified. The Minitab-18 program is used to apply the Taguchi method to determine the level of importance and optimum machining parameters. The findings offer valuable insights for manufacturers to enhance product quality and optimize manufacturing processes.