Aim: The aim of the present study was to compare differences in outcomes following the repair of traumatic and non-traumatic rotator cuff injuries at varying time points. Methods: This retrospective study enrolled patients attending to the Department of Orthopaedics. It was approved by our Institutional Review Board, and the requirement for informed consent was waived by the committee owing to the retrospective nature of the study. Among the 112 rotator cuff injury patients whose charts were reviewed, 100 met the inclusion criteria. Results: Traumatic RCI patients had 27 early and 23 delayed repairs. Early repair was performed on 22 non-traumatic RCI patients and delayed repair on 33. In the trauma and non-trauma groups, the early repair and delayed repair subgroups had similar tendon involvement. Preoperative VAS, ASES, Constant, and UCLA scores were similar for early and delayed trauma healing. Preoperative VAS, ASES, Constant, and UCLA scores were similar for early and delayed repair patients in the non-trauma group. Conclusion: Early treatment of traumatic rotator cuff injuries improved range of motion, discomfort, and postoperative re-tear compared to delayed repair. Thus, severe rotator cuff injuries are best treated with early arthroscopic surgery. However, early repair did not improve postoperative joint function and morbidity for non-traumatic rotator cuff injuries.