In this paper, a novel approach to increase the wire electrical discharge machining performance by using small diameter wire is presented. As wire in wire electrical discharge machining (WEDM) is the only externally added into the intrinsic system, its role is determinant in the performance of WEDM. It is characterised by essential mechanical, electrical, and thermal properties. Here 0.15, 0.20, and 0.25 mm diameter zinc coated wire is used, on 8, 10 and 12 mm thick rectangular blocks of Inconel718, to investigate the performance measures such as the material removal rate (MRR), and surface roughness (SR). Taguchi L27 orthogonal array is employed to ascertain the effect of varying diameter. It is observed that MRR and SR. are greatly influenced by wire diameter. A small size wire diameter is proved to be better on all accounts, promising a high MRR with lower SR. Further SEM studies revealed that the alterations such as debris and oxide deposition seen on the surface are very less and is acceptable with no foreign particle accumulation on the surface revealed by EDAX. There are no cracks developed in the cutting with small diameter wire.