Objective: The aim of this study is to evaluate shoulder function and preoperative and postoperative electrophysiological changes related to the spinal accessory nerve with reference to neck dissection technique. Materials and Methods: We evaluated shoulder function by pain, strength and range of motion in a total of 35 neck dissection cases of 29 patients with head and neck cancer or thyroid papillary cancer. Electrophysiologic studies were performed before surgery, after third postoperative weeks and 6 months respectively. The results of each test according to the types of neck dissection were compared. Results: Clinical parameters of shoulder function and electrophysiologic study showed deterioration in early postoperative periods and improvements in late postoperative periods when the spinal accessory nerve was spared and permanent nerve damage was observed in radical neck dissection. There were correlations between the clinical parameters and electrophysiologic studies. Conclusion: The shoulder function after spinal accessory nerve sparing procedure is better than the function after nerve sacrificing procedure.