Diabetic neuropathy is one of the most frequent peripheral neuropathies, which result in many serious clinical problems. The purpose of this study is to fined the most sensitive electrodiagnostic examination method for the early diagnosis of diabetic neuropathy, and to investigate the correlations between electrodiagnostic findings and clinical factors such as age, sex, Body Mass Index(BMI), duration of diabetes mellitus, HbAIC level, and other diabetic complications. Seventy-four diabetic patients were examined with peripheral nerve conduction(NCS), F-wave and sympathetic skin response(SSR) studies. The average age of the patients was 53.0(12.7 year, and average duration of diabetic mellitus was 8.0(6.4years, Sixty-seven patients had suffered from peripheral or autonomic neuropathic symptoms and 29patients had suffered from the diabetic complications Forty-five patients (60.8%) among 74 showed abnormal findings in NCS, In F-wave study, 24 patients(33.8%) among 71 had abnormal findings, and 49 patients(66.8%) among 74 were found to have abnormal findings in SSR study. The duration of diabetes mellitus and BMI had significant effect on the results of electrodiagnostic studies. Peripheral nerve conduction study was especially strongly affected by the duration of diabetes mellitus. In the group of patients with duration of diabetes mellitus less than 5 year, the frequency of abnormal findings was higher with SSR than with NCS. This findings can suggest that autonomic nervous system could be involved earlier than the peripheral nervous system in diabetic neuropathy. In conclusion, peripheral nerve conduction and sympathetic skin response studies are the sensitive electrodiagnostic method for detection of diabetic neuropathy in early stage.