Two hundred and forty-five persons, exposed to hand—arm vibration, were examined clinically and by measuring the conduction velocities of the motor and sensory fibres of the ulnar and median nerves (N.). The results are compared with X-ray findings of the cervical vertebral column and the elbow joint. The clinical and EMG studies indicate mostly isolated damage of the N. medianus, which resembles the carpal tunnel syndrome. Isolated damage of the N. ulnaris was usually observed simultaneously with damage to the elbow-joint processes (arthropathy). Combined lesions of both nerves occurred predominantly in subjects with a diagnosis of vasoneurosis. A small group of persons with traumatic vasoneurosis, a group with industrial vasoneurosis and a control group were also examined by EMG. The results indicate that in the initial stage of vibration damage, the vessel component is an important factor leading to ischemic neuropathy.