Interest in platelet-rich plasma (PRP) has skyrocketed over the last decade, with a growing body of research contributing to both excitement and skepticism regarding its use. Despite mixed opinions in the medical field, interest from the public has fueled increased utilization of PRP for musculoskeletal conditions, particularly those that are difficult to treat such as chronic, degenerative tendinopathy and osteoarthritis. PRP\'s reputation as a \"natural healer\" and stories in the lay press featuring the use of PRP by professional athletes and celebrities has created a lucrative market for PRP even absent insurance reimbursement, casting further doubt regarding motivation for use by some practitioners. Research of PRP is clouded by the fact that PRP is a heterogeneous term representing a variety of different platelet preparations and there are many variables in technique and postprocedure rehabilitation, all of which may have significant effects on outcome. This article discusses definitions and classification of PRP, reviews rationale and evidence for use of PRP in chronic tendon injuries and osteoarthritis, and looks at future directions.