New developments in material science have developed high-strength temperature-resistant materials (HSTR)with many extraordinary abilities. Now a days these advanced and smart materials such as Nickel-basedsuper alloys, stainless steel and tool steel are the demands of automotive, aerospace, electronics, medicaldevices and communication industries for production of more durable and reliable products. Machining ofthese materials is a challenge and traditional manufacturing techniques are often found unfit for the purpose.Electrochemical machining (ECM) provides the alternative to traditional or conventional machiningprocesses without a direct contact between the tool and the workpiece, with high material removal rates,irrespective of diverse mechanical properties of the workpiece. Even though ECM has a great potential, theprocess is still not fully explored and its research is in process. ECM process involves number of phenomenasuch as electrochemistry, mass transfer, heat transfer and hydrodynamics taking place simultaneously andleads to different material removal rate at each point on the anode surface (Workpiece). Due to this it is verydifficult to predict the anode profile accurately in ECM process. For better understanding of the ECM processto improve the performance the basic electrochemistry involved is reviewed and presented in this paper.