This randomized, multi-centre, national trial will determine whether an arthroscopic or mini-open repair provides better quality of life for patients with small or moderate sized rotator cuff tears. A national consensus meeting of investigators in Joints Orthopaedic Initiative for Shoulder Trials (JOINTS) identified this question as the top priority for shoulder surgeons across Canada. The primary outcome measure is a valid quality-of-life scale (Western Ontario Rotator Cuff (WORC) that addresses 5 domains of health affected by rotator cuff disease. Secondary outcomes will assess rotator cuff functionality (ROM, strength, constant score), secondary dimensions of health (general health status (SF-12) and work limitations) and repair integrity (MRI). Outcomes are measured at baseline, at 6 weeks, 3, 6, 12 and 24 months postoperatively by blinded research assistants and musculoskeletal radiologists. Patients (n=250) with small or medium-sized cuff tears identified by clinical examination and MRI who meet eligibility criteria will be recruited. This sample size will provide 80% power to detect (statistically) a clinically important difference of 20% in WORC scores between procedures after controlling for baseline WORC score ("=0.05). A central methods centre will manage randomization, data management and monitoring under supervision of experienced epidemiologists. Surgeons will participate in either conventional or expertise-based designs according to defined criteria, to avoid biases from differential surgeon expertise. Mini-open or all-arthroscopic repair procedures, will be performed according to a standardized protocol. Central Adjudication (of cases), Trial Oversight and Safety Committees will monitor trial conduct. The investigators will use an analysis of covariance (ANCOVA), where the baseline WORC score is used as a covariate, to compare the quality of life (WORC score) at 2-years post-operatively. As a secondary analysis the investigators will conduct the same statistical test but will include age and tear size as covariates with the baseline score. Enrollment will require 2 years and follow-up an additional 2-years.