PURPOSE: To find out the consequences of the surgical treatment of acromioclavicular joint dislocation, using modified Phemister technique with Mersilene tape augmentation. MATERIALS AND METHODS: We chose 26 patients who were able to follow up 1 year or more among the patients who were diagnosed as acromioclavicular joint dislocation in our hospital through February 2001 to March 2003 and took modified Phemister surgery with Mersilene tape augmentation. Patients with clavicle fracture were excluded. Evaluation of the surgical results was done with the condition or pain, function, range of motion by using Imatani evaluation system, and preoperative, postoperative and last follow up radiographs. RESULTS: Most of the cases showed satisfactory result. Clinical evaluations were 16 excellent (62%), 10 good (38%), radiological evaluations were 14 excellent (54%), 10 good (38%), 2 fair (8%), and no poor group. On the final follow up six cases showed vertical translation, but none had clinical symptoms. Seven cases showed a little inflammation at where pin were inserted, but after the removal of the pin, the inflammation was gone. CONCLUSION: The modified Phemister surgery for acromioclavicle dislocation is simple, but we can obtain strong fixation, and there is no burden of the removal of the metal plate, or complication of re- dislocation after the removal of the pin, so it is thought as a very effective surgery.