Background Diabetic patients are known to have poor wound healing and worse outcomes following surgeries. The purpose of this study is to evaluate diabetes status and complications for patients receiving open rotator cuff repair. Methods Patients undergoing open rotator cuff repair from 2006 to 2018 were identified in a national database. Patients were stratified into 3 cohorts: no diabetes mellitus, non-insulin dependent diabetes mellitus (NIDDM), and insulin dependent diabetes mellitus (IDDM). Differences in demographics, comorbidities, and complications were assessed with the use of bivariate and multivariate analyses. Results Of 7678 total patients undergoing open rotator cuff repair, 6256 patients (81.5%) had no diabetes, 975 (12.7%) had NIDDM, and 447 (5.8%) had IDDM. Bivariate analyses revealed that IDDM patients had increased risk of mortality, extended length of stay, and readmission compared to non-diabetic patients ( p < 0.05 for all). IDDM patients had higher risks of major complications and readmission relative to NIDDM patients ( p < 0.05 for both). On multivariate analysis, there were no differences in any postoperative complications between the non-diabetic, NIDDM, and IDDM groups. Discussion Diabetes does not affect postoperative complications following open rotator cuff repairs. Physicians should be aware of this finding and counsel their patients appropriately. Level of Evidence: III