20 patients with a chronic full-thickness rotator cuff tear were randomized to undergo arthroscopic repair either with or without the application of leukocyte- and platelet-rich fibrin (L-PRF). The purpose of this study was to determine if L-PRF increased vascularization of the rotator cuff over the first 3 postoperative months. The results at 6 weeks indicated that vascularity was, indeed, improved in the group treated with L-PRF. However, the difference between groups at 12 weeks was not statistically significant. Both groups were observed to have similar repair integrity, repair quality, and clinical outcomes over the 3-month follow-up.