The purpose of this article was to report an arthroscopic treatment method for greater tuberosity malunion. Eight patients with malunion of the greater tuberosity were treated by arthroscopic acromioplasty, detachment of rotator cuff, tuberoplasty of the greater tuberosity and repair of the rotator cuff. On the basis of the UCLA rating scale, the overall score increased from 11.1 (range 9-14) to 30.2 (range 25-35) postoperatively, with one excellent result, six good results, and one poor result. All patients had less pain than preoperatively. Full activity level was achieved in two patients, five patients had only slight functional restriction, and one patient had mild limitation in activities of daily living. Seven patients returned to their previous occupations without restrictions. One patient did not return to work because of residual upper extremity weakness. We conclude that arthroscopic tuberoplasty is a good method for the treatment of greater tuberosity malunion.