OBJECTIVE: The purpose of this study was to determine the relationship of abnormal parameters in commonly tested peripheral nerves and clinical findings in diabetic neuropathy. METHOD: Parameters in tested peripheral nerves are all 18 as follows; Distal latency and amplitude of median motor, median sensory, ulnar motor, ulnar sensory, tibial motor, peroneal motor, and sural sensory (14) plus conduction velocity of median motor, ulnar motor, peroneal motor, and tibial motor (4). Person who had at least one abnormal parameter out of 18 parameters counted as abnormal group and then it was divided 3 groups depending on numbers of abnormal parameter as follows; one to two abnormal parameters as mild group, three to five as moderate group, and more than 6 as severe group. RESULTS: The factors which were correlated with number of abnormal parameters on nerve conduction study (NCS) were 1) duration of diabetes mellitus and 2) age of patients but not the level of HbA1c (p<0.05). The involved nerves in the order of frequency were sural sensory (49.7%), peroneal motor (43.2%), median sensory (32.7%), ulnar sensory (31.2%), median motor (29.6%), and ulnar motor (23.1%). In persons having mild grade on NCS, amplitude of sensory nerve action potential (SNAP) was more frequently involved than distal latency of SNAP. Among the parameters, amplitude of median compound muscle action potential (CMAP), amplitude of ulnar CMAP, distal latency of ulnar SNAP and the amplitude and distal latency of tibial CMAP seemed to be less affected in diabetic neuropathy. CONCLUSION: The amplitude of SNAP seemed to be valuable parameter in detection of early diabetic neuropathy.