Abstract- Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes. EDM process is based onthermoelectric energy between the work piece and an electrode. A pulse discharge occurs in a small gap between the work piece and theelectrode and removes the unwanted material from the parent metal through melting and vaporising. The electrode and the work piecemust have electrical conductivity in order togenerate the spark. There are various types of products which can be produced using EDMsuch as dies and moulds. Parts of aerospace, automotive industry and surgical components can be finished by EDM. This paper reviewsthe research trends in EDM on ultrasonic vibration, dry EDM machining,EDM with powder additives, and EDM in water.Index Terms - Electric Discharge Machining, Dry EDM, Wire EDM, Ultrasonic EDM, EDM with powder additives, EDM in water,Kerf Width, Spark Gap