Advancements in machining science provided a wider scope for the development of composites and advance materials. As the researches are going on into this field newer materials are coming into existence, having complex meteorological structure and high mechanical-resistance ability. Due to the extreme strength, toughness and hardness of these materials advance machining processes are taking over the conventional machining processes in this field. Electrical discharge machining (EDM) is one of its own kind of advance machining process, which has been used during this research work. This study investigates the performance and surface finish of cryogenic treated and non-treated copper tool electrode during electrical discharge machining of Hastelloy C-4. Effect of cryogenic treatment, current, Pulse on time, Pulse off time was investigated on surface roughness. The comparative study reveals that pulse on time, tool electrode and current are the most influential parameters that affect Performance and surface finish during EDM. The study shows that cryogenic treated copper tool generates better surface finish than the conventional copper tool electrode. Microstructural studies show that thick recast layer was observed in case of cryogenic treated copper electrode and also deep shallow craters were found at higher value of current.