Objectives : To evaluate the effects of arthroscopic acromioplasty and debridement for partial thickness articular side rotator cuff tears, Method: We divided 97 patients into 2 groups according to treatment protocol, with both groups having confirmed intra-articular partial tears of the rotator cuff. In group Ⅰ, we debrided the frayed and fibrotic cuff margin while in group II, we performed subacromial decompression in addition to debridement. After the surgery we checked all the patients with the modified UCLA shoulder rating scale. Results: The follow-up observation 12 months after surgery revealed that 44 patients in group I were rated as excellent in 32 cases, good in 10 cases, fair in 1 case, and poor in one case, while 53 patients in group II, were rated as excellent in 38 cases, good in 17 cases, and fair in 2 cases. Twenty-four month after surgery we observed that patients in group I were rated as excellent in 23 cases, good in 16 cases, fair in 4 cases, and poor in 1 case, while patients in group II were rated as excellent in 34 cases, good in 17 cases, and fair in 6 cases. Conclusion: The use of acromioplasty on partial thickness tears of rotator cuff, even in the cases of intra-articular nature, is preferable to the procedure performed without it.