Injuries to the spinal accessory nerve are rare and mostly iatrogenic. Pain, impaired ability to raise the ipsilateral shoulder, and scapular winging on abduction of the arm are the most frequently noted clinical manifestations. As a seldom case, a 20 year-old male with spinal accessory nerve palsy after penetrating trauma by gunshot was reported. Three months after the injury, he was complaining about left arm pain in abduction to shoulder level and a decreased range of movement. On physical examination, wasting of the left trapezium with loss of nuchal ridge and drooping of the shoulder were found. On neurological examination of the left trapezius and sternomastoid muscles, motor function were 3/5 and wide dysesthesia on the neck, shoulder and ann was present. The bullet entered just above the clavicle and exited from trapezium. Radiological studies were normal, where electromyography (EMG) showed neuropathic changes. Surgical exploration showed the intact nerve lying on its natural course and we performed external neurolysis for decompression. The postoperative period was uneventful. Dysesthesia has diminished slowly. He was transferred to physical rehabilitation unit. In his clinical control after 3 months he had no dysesthesia and neurological examination of the left trapezius and sternomastoid muscles motor function were 4/5. EMG showed recovery in the left spinal accessory nerve.