Resistance spot welding process is one of the oldest methods used to join sheet metals using a combination of heat,pressure and time parameters.It is an economical and highly productive process and is, therefore, being used in various manufacturing industries and has a great future ahead.The present discussion deals with a critical review of spot welding carried out by different investigators.The review also includes the various methods of optimization of process parameters.The sheets to be welded are clamp together between the electrodes and current is allowed to flow.The plates get heated at the interface due to the resistance in the path of current flow.The pressure applied on the electrodes causes the heated region to yield and get squeezed together to form a weld nugget.