In order to evaluate the effects of trichloroethylene (TCE) on the central and autonomic nervous system, the brain stem auditory evoked potentials (BAEPs) and the electrocardiographic R-R interval variability (CV(rr)) were measured in three groups of workers (11) working in TCE degreasing process, workers (4) exposed to lead and two groups of workers (12) not exposed to any kinds of neurotoxicants. Two components of the CVrr reflecting parasympathetic activity (C-CV(rsa)) and sympathetic and parasympathetic activities (CCV(mwsa)) were examined. The TCE workers were exposed to TCE at the level of less than 1 hour per week while the degreasing material was changed. There were no differences in the latencies of BAEPS and CV(rr) and the components of the CV(rr) between control and TCE and lead groups. However, two lead workers had the blood lead level of less than 60 g/dl recommended as present biological guideline by the Ministry of Labor, showed the delayed latencies of V5 and I-V in BAEP. This results suggested that intermittent TCE erposure didn't affect the auditory nervous pathway and the autonomic nervous system, however, lead exposure might affect the central nervous system at the level of less than 60 g/dl in blood lead.