Abstract Electrically conductive polycrystalline composite diamond (EC-PCD) material, which consists of electrically conductive diamond particles, has recently been developed for the purpose of providing the material with both excellent tool property and machinability. This paper deals with material properties and electrical discharge machinability of EC-PCD. The result shows that the EC-PCD is superior in heat resistance to conventional PCD by a factor of about 200 °C. And the EC-PCD shows low frictional wear at high temperature in a sliding test against a stainless steel disk. Furthermore, processing speed of EC-PCD is more than 7 times higher than that of conventional PCD in EDM.