Purpose: To study the effects on pain as the main outcome parameter and on function and cuff integrity as the secondary outcome parameters after arthroscopic rotator cuff repair in the short term comparing the abduction brace with an antirotation sling for postoperative shoulder immobilization., Methods: Eligible patients were between the ages of 18 and 75 years who were diagnosed with a traumatic or degenerative tear of the supraspinatus and/or infraspinatus tendon, confirmed by magnetic resonance imaging, for which an arthroscopic footprint repair was indicated and performed. Patients were randomly allocated to the antirotation sling or abduction brace group. Postoperative pain and use of analgesics were accurately registered up to 3 months after surgery using a patient diary. Follow-up examinations including the Constant-Murley score, Western Ontario Rotator Cuff index, and glenohumeral range of motion were scheduled 6 weeks, 3 and 6 months, and 1 year after surgery., Results: The average level of pain measured directly postoperation up to 1 year after surgery was not significant different between groups. Postoperatively, function scores and glenohumeral range of motion improved significantly for both groups; however, no differences were observed between groups. No retears were observed on ultrasonograph 3 months after surgery., Conclusions: In the short term, the level of pain, function, and quality of life were not significantly different between the use of an abduction brace and that of an antirotation sling after arthroscopic rotator cuff repair. Based on these findings, the abduction brace used in this study does not seem to be the solution for decreasing the pain experienced in the first postoperative weeks after arthroscopic rotator cuff repair, and both are recommendable., Level of Evidence: Level I, randomized controlled trial., (Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)