Rotator cuff tears are a common cause of shoulder pain and disability. Because they combine both traumatic and degenerative elements, the surgical repair can be challenging. Even after surgical intervention, tendon residual defects or "retears" often develop. Risk factors for tendon "retears" include patient age, number of tendons involved, tear size, and smoking. Platelet-rich plasma (PRP) is a supraphysiological concentration of platelets, which may be able to positively augment rotator cuff tendon healing. Not all PRPs are the same and those containing higher leukocyte levels may be detrimental to tendon healing. Thrombin activation triggers an immediate release of growth factors from the PRP and may actually inhibit some parts of the healing response. As yet, the clinical data does not conclusively prove a benefit from PRP, but discernment is required in evaluating the published results. As different PRPs may act differently and the results may be dose dependent requiring more PRP to achieve a beneficial threshold. How success is measured (clinical outcomes vs. intact cuff tendons) and how long the patients are followed are also critical items. Currently, the PRP fibrin matrix version holds the greatest promise for improving clinical success after rotator cuff tendon repair.