WEDM is used for cutting intricate or complicated shapes which are not possible with conventional machining methods. Wire cut EDM is a cutting process used widely where conventional machining processes are not useful. A metal wire with a Dielectric medium travels through a path and perform machining procedure . The main objective of the present work is to investigate the effects of various WEDM process parameters on the machining quality and to obtain the optimal sets of process parameters like Pulse-ON time, Pulse-OFF time, current, wire feed are studied by conducting an experiment. Taguchi Method is to design the experiment. L16 orthogonal array is used to conduct the experiment. An AISI-4140 (carbon steel) is used as a work piece material in the form of square bar. The surface roughness (SR) is selected as response variable.