Twenty six consecutive patients with superior labrum anterior to posterior (SLAP) lesions of the shoulder involving the hiceps attachment to the labrum were fixed with biodegradable tack through a new lateral portal arthroscopically and reviewed to evaluate the efficacy of the biodegradable tack tixation in the unstable SLAP lesion. The tack was placed at the posterosuperior aspect of biceps attachment and directed toward anteroinferior via lateral portal just lateral to the acromial margin. Mean follow up duration was 18 months (range, 8 to 27). According to Snyder s classification, 24 cases were type ll, 1 case was type III and 1 case was type IV. lsolated SLAP lesion was nine cases (35%,) in our series. Thirteen cases were associated with the unidirectional anterior instability, one case with the multidirectional instability, 2 cases with the full thickness tear of the rotator cuff and 1 case with the acromioclavicular injury. Preoperative scores increased postoperatively by using the American Shoulder and Elbow Society (ASES) evalualion system in all cases. ln isolated SLAP lesions, pain scores improved from 3.0 to 4.2, stability scores from 3.7 to 5.0, and function scores from 2.7 to 3.4. In associated SLAP lesions, pain scores improved from 3.2 to 4.2, stability scores from 3.5 to 4.8 and function scores from 3.1 to 3.9, Overall scores improved from 71 to 93 in associated SLAP lesions and improved from 67 to 90 in isolated lesions. Eiehteen patients(69%) achieved excellent results and 6 patients(23% ) ohtained good results. And there were no complications related to the use of biodegradable implant. Thus, arthroscopic fixation is recommendable in the management of the unstable SLAP lesions.