The sympathetic skin response (SSR) is the potential generated by sweat in response to different stimuli. This potential has a waveform that habituates with closely repeated stimuli and a latency of 1.3-1.5 s at the hand and 1.9-2.1 s at the foot. It has been used to study the peripheral sympathetic system in peripheral nerve diseases. The response is absent in many cases of peripheral neuropathy, often in the presence of autonomic symptoms. SSR has also been used to study a few diseases that may affect the central sympathetic system. This review outlines the history, physiopathogenesis, and analysis of SSR as well as general techniques used in its study. The reported association of SSR with peripheral and central nervous system diseases is also presented.