In order to clarify the mechanisms of cold temperature on vibration-induced white finger (VWF), three groups of forestry chain saw operators served as the subjects of this study. Groups I and II worked in a cold high-altitude area, and group III worked in a warm low mountain climate. Group I workers had VWF sign [VWF(+)] but groups II and III did not [VWF(-)]. In the present study, finger nailfold microcirculation before and after cold exposure, finger skin sympathetic alpha receptor response, and sympathetic skin response were measured. The results showed that there was no significantly different neuropathy in any of the groups. However, vibration-induced microcirculatory disturbances including blood stasis and red blood cell aggregation were more prominent in VWF(+) group, whereas both of the VWF(-) groups (groups II and III) had no significant difference in microcirculatory disturbances. This suggests that the severity of the microcirculatory disturbances is dose-effect correlated and is aggravated by cold in vibration syndrome. Thus it can be realized that a cold working environment is an important contributing factor in causing microcirculatory disturbances of VWF.