Purpose: We wanted to evaluate the effectiveness of inferior capsular plication for treating the anterior instability of the shoulder by comparing the prospective outcomes and the incidence of complications of the group (group1) that underwent arthroscopic vertical shift of the anteroinferior capsulo-labral complex and plication of the anterior band of inferior glenohumeral ligament and the group (group2) that underwent inferior capsular plication that was augmentated by the same method. Materials and Methods: From March 2005 to August 2007, we compared group 1 (42 cases) that underwent arthroscopic vertical shift of the anteroinferior capsulo-labral complex and plication of the anterior band of the inferior glenohumeral ligament and group 2 (33 cases) that underwent augmentated inferior capsular plication for recurrent anterior instability of the shoulder. The mean age was 22.5 years (range: 17~31 years) in group I, and 21.8 years (range: 16~30 years) in group II. The mean follow up was 23.5 months (range: 12~45 months in group I, and 20.1 months (range: 12~49 months) in group II. We checked the Rowe score and ROM preoperatively and at postoperative 6 months, 1 year and at the last follow up and we compared the incidence of complications. Results: The Rowe score increased from a preoperative mean of 20.6 to the last follow up mean of 86.8 after surgery in group I, and the Rowe score increased from a preoperative mean of 20.5 to the last follow up mean of 94.1 after surgery in group II. For the anterior instability of the shoulder, arthroscopic reconstruction had a good outcome in all of the cases, but group II had better outcomes and less complications than did group I (p<0.05). Conclusion: We thought that arthroscopic vertical shift of the anteroinferior capsulo-labral complex and plication of the anterior band of the inferior glenohumeral ligament with inferior capsular plication can lower the complication rate and show better outcomes.