We report two cases of migration of K-wires from the acromioclavicular joint to the neck. A 73-year-old man complained of right shoulder pain for one month and had undergone orthopedic surgery because of acromioclavicular joint dislocation about 27 years earlier. Another 56-year-old man complained of left shoulder pain and neck pain for 5 years and had undergone orthopedic surgery because of acromioclavicular joint dislocation about 25 years earlier. In both cases, we took X-rays to look for the cause of shoulder pain and discovered broken and migrated K-wires in the neck. We removed the K-wires from the trapezius muscle and the paraspinal muscle respectively. K-wire fixation technique is simple and effective but should be followed up with X-rays periodically. In addition, we should warn patients of the possibility of migration of K-wire. And it is desirable for us to avoid using K-wire near major neurovascular structures like the sternoclavicular joint and the clavicle.