Sympathetic skin response (SSR) is defined as a minute change of skin potential after electrical stimulation. This test measures the change in voltage that originates from the surface of the skin and is attributed to sudomotor activity. The aim of this study was to define the criteria for validation of the responses. 40 normal subjects (20-73 yr of age) with non-sympathetic dysfunction were tested and SSR was generated from all subjects. The SSR latency was 1,331.22± 177.51 ms in the right palm, 1,331.74±156.42 ms in the left palm, 1,851.79±220.99 ms in the right sole, and 1,874.10± 215.01 ms in the left sole. Also, the SSR amplitude was 595.83±221.16 mV in the right palm, 605.33±226.45 mV in the left palm, 291.76±133.36 mV in the right sole, and 288.77±129.70 mV in the left sole. The SSR latency and amplitude had no significant difference between the right and left sides. The SSR latency was consistently shorter (p<0.001) and the SSR amplitude was higher (p<0.001) in the feet than in the hands. P-type (32 subjects, 75%) was more than N-type (8 subjects, 25%) in the SSR wave forms. The SSR latency and amplitude in palms/soles were closely correlated with age (p<0.05) and height (p<0.05). The SSR test is one method for assessing impairment of sympathetic fibers in peripheral neuropathy as well as a disorder of sympathetic system in other diseases and so our results from normal healthy subjects can be used as clinical criteria for the SSR test.