OBJECTIVES: To investigate the hand-arm vibration syndrome (HAVS) among symptomatic swagging workers exposed to hand-arm vibration, using medical evaluation and measurement of workplace vibration. Furthermore, to evaluate the neurophysiological METHODS: Four workers showing symptoms relevant to HAVS were evaluated. Medical evaluation consisted of medical interview, questionnaire, nail-bed compression test, and sensory perception tests for vibration and pain. Some other diseases were excluded by a medical interview, hematological assessment, and urinalysis. Cold provocation test was used to assess the peripheral vascular changes, and a nerve conduction velocity (NCV) test was implemented to ascertain the peripheral neural changes. Pegboard, hole plate, and tapping board tests were performed to assess motor nerve function. The hand-arm vibration acceleration levels of the swagging machines were measured. Six months later, follow-up NCV tests were performed. RESULTS: The actual exposure time to vibration was not longer than 15 minutes per day. The hand-arm vibration acceleration levels of the swagging machines, according to actual exposure time, were from 3.63 to 12.98 m/sec2, by ISO 5349. The vibratory perception thresholds and the recovery time of a nail color following finger cooling were significantly increased in all four workers. The perception of pain was mildly increased. The nerve conduction studies at first diagnosis and follow-up showed multifocal neural impairment caused by vibration. However, we could not rule out the concomitant presence of the carpal tunnel syndrome in one worker. CONCLUSIONS: These results show that HAVS can be caused by hand-arm vibration in swagging workers. Interestingly, the NCV results suggested that vibration-induced neural conduction impairments could vary, and need to be interpreted cautiously.