Due to wide range of applicability of hard and difficult-to-machine materials like super alloys (Ti-alloys, Inconel, hastalloy etc), advanced ceramics and composite materials, researchers are striving to conduct the various machining operation over it. Electrical discharge diamond drilling (hybrid process) process has been carried out on Inconel 718 using Taguchi L9 orthogonal array (OA). The effects of process parameters such as peak current (I), pulse-on time (Ton), pulse-off time (Toff) and drill speed (DS) on metal removal rate (MRR) and surface roughness have been studied to optimize and improve the process capabilities. In this study MINITAB 18 software was used to find the effects of each parameter on performance measures and to predict the setting of control parameters. Analysis of variance (ANOVA) has been performed to identify the process parameters which significantly affect the performance measures such as MRR and SR. The significant parameters have been identified critically and their effects on performance measures have been studied. Optimal parametric combinations were predicted for best result on MRR and ASR. The percentage variations between predicted and experimental values of metal removal rate and surface roughness during confirmation experiment have been found within 10%.