In clinical settings, electrodiagnosis is used for the differential diagnosis of neuropathy and myopathy, as well as detremining severity and localization of lesions in the neuromuscular system. By many authors, various methods of the study and factors influencing the results were verified so far. However, the results vary according to methods or influencing factors during electrodiagnostic studies. Since there has been no standardization in methods of the study and study environment, we sometimes feel difficulties in interpretation of study results and in exchage of findings of study among laboratories. In this study, we have collected standards and norms used by different electrodiagnostic laboratories in Korea, hoping that we can come up with one nationwide standards and norms in Korea.