Twenty-three patients with hand-arm vibration exposure and diagnosed vibration syndrome were given a thorough clinical and neurophysiological examination, together with finger strain gauge plethysmography. Eleven of the patients were forest workers regularly using chain saws (low frequency vibration exposure), and twelve were metal grinders (higher frequency vibration exposure). Both groups had significantly lower finger blood pressures than healthy controls, and comparisons between the groups indicated that the mean values tended to be lower in the grinders. The findings suggest that hand-arm vibration exposure is associated with obstructive changes in the distal arteries of the fingers, and that vibration frequency is one of the factors determining the severity of the changes and the time of onset of the symptoms.