Abstract. The paper presents the experimental analysis and multi-response optimization of EDM process parameters during machining of Nimonic 90 work material. The experiment has been conducted at different parametric setting considering discharge current, pulse-on-time and pulseoff-time as process parameters. Taguchi L9 orthogonal array has been used for experimental design. The effect of various parameters on response such as material removal rate and surface roughness has been studied with the help of suitable plots. The Grey Relational Analysis has been utilised for obtaining the optimal parametric combination.