Background: Tendons are dense connective tissues composed primarily of a highly organized type I collagen extracellular matrix (ECM). Which enables a tendon to perform its mechanical function of force transfer. Platelet rich plasma (PRP) serves as a growth factor agonist and has both mitogenic and chemotactic properties. Aim: investigation the effect of PRP in tendon healing in rats, and evaluation the rate of possible complications. Materials and Methods: The study included (35) rats, (5) rats only used as donors for PRP, while (30) rats separated as PRP group:(1); injection, group (2); spray, group (3); mixed. The left leg in all rats (control group) receives nothing, while the right leg receives PRP as separated groups. Each rat was kept in a separated cage and checked on until the end of the follow up period (15-30) day. After (15) and (30) days post-treatment, (5) rats of each group were sacrificed, and their Achilles tendons were extracted and examined histopathologically. Stained sections examined for the number of the inflammatory cells / HPF, the ratio between collagen 1 and collagen 3 and the arrangement of the collagen fibers. Results: Stained sections shows differentiation in levels between collagen 1 and collagen 3, we did not observe altered level of collagen III in the PRP-treated tendons, an increased level of Collagen I was measured in the PRP treated tendons. Furthermore, PRP inhibits proliferation of macrophages could prevent an excessive inflammation during the early phase of healing, and could promote proliferation, metabolic activity, and differentiation of the mesenchymal cells into active tenocytes. Finally, it was obvious that PRP not only enhances healing, but also promotes the regeneration of the fibrocartilage zone in the wounded rat ATs and decrease adhesions. From this study, PRP treatment did high promoting the formation of fibrocartilage in wounded rat ATs. It did enhance healing by inducing collagen 1 expression. The results indicate that collagen 1 fibers formed in the wounded rats ATs due to PRP treatment. This may partially explain why PRP treatment increased the tensile mechanical strength of the wounded ATs. Compared with treatment without PRP, it contained scar tissue formation, characterized by the presence of excessive collagen (iii), which is typically disorganized, and weak in mechanical strength. Finally, Histo-pathological analysis showed well organized arrangement of collagen fibers and proteoglycan formation in the wounded ATs in the PRP group. Conclusion: With PRP treatment appeared to have healed the injured Ats, without, PRP treatment showed poor healing without fibrocartilage tissue formation in the ATs. We recommend using PRP treatment to human tendon pathologies.