Purpose : To evaluate effectiveness of arthroscopic distal clavicle resection for chronic stage 2 acromioclavicular dislocation. Material: 6 patients who had failed to respond to physical therapy were evaluate more than 6 months prospectively, which were treated with arthroscopic distal clavicular resection from february 1998 to January 2001. Result : The median preoperative Constant score changed from 32 of 100 to 37 of 100 at 3 to 6 weeks, to 49 of 100 at 3 months and to 69 of 100 at 6months. Improvement was achived at mean follow up more than 6 months after surgery. Overal $83\%$ of patient were satisfied with this procedure. but the remained case was unsatisfied because symptom was not improved more than 6 months Conclusion : Arthroscopic distal clavicle resection is useful method to treatment for chronic stage 2 acromioclavicular dislocation.