Introduction: Osteoarthritis (OA) represents a failure of the di-arthrodial, synovial lined joint. Among the elderly, knee Osteoarthritis is the leading cause of chronic disability [1]. Because of the increased lifespan and obesity the prevalence of osteoarthritis is in the rise in India. Aim of the Study: Whether platelet rich plasma is useful in OAknee or not. Objectives: To evaluate the role of Autologous Platelet Rich plasma (APRP) in the treatment of patients presenting with primary osteoarthritis and to analyze whether it could be a cost effective disease modifying measure. Materials and Methods: Total 100 OA Knee cases are selected from the Katuri Medical College and Hospital, randomly. First 50 were given A PRP injection to the OA Knee, Next 50 were given normal saline. Platelet-Rich Plasma: Platelets are cytoplasmic fragments of megakaryocytes, that are formed in the marrow [26] and are approximately 2 μm in diameter. They contain more than thirty bioactive proteins, of which many of them have a fundamental role in hemostasis or in tissue healing [28]. Fundamental protein growth factors which are actively secreted by platelets will initiate all the wound healing process [29] PRP includes three proteins in blood which is known to act as cell adhesion molecules: Fibrin, fibronectin and vitronectin [30]. Discussion: Osteoarthritis is a disorder of synovial joints characterized by focal loss of hyaline cartilage with proliferation of new bone and remodeling of joint contour, mainly due to uncoupling of balance between cartilage regeneration and degeneration. Osteoarthritis is a dynamic repair process of synovial joints that may be triggered a variety of insults. We in our study had randomly chosen 100 patients with classic findings of Osteoarthritis and divided them in to two groups. Both the groups were comparable on baseline characteristics of age, height, weight, BMI, pre injection WOMAC score. Fifty of these patients were administered an intra articular injection of Platelet Rich Plasma and other fifty received Normal Saline. The Efficacy of Platelet Rich Plasma in reducing pain, stiffness and physical function were assessed and scored on WOMAC index for both study and control group. The Results were analyzed using unpaired ‘t’ test and chi- square test. Age distribution revealed mean age in group I to be 53.14 and the mean age in Group II was 53.68. Outcome Analysis: The study group and the control group are advised to follow up at 6 weeks, 3 months and 6 months. Outcome analysis for the efficacy was done for reduction in pain, reduction in stiffness and improvement in physical function using WOMAC scale. The Patients were also assessed for reduction in pain using Visual analog scale both at pre injection and at 6 months post injection. Conclusion: Our study has thrown up an interesting choice of treatment modality using Platelet Rich Plasma in the treatment of Knee Osteoarthritis and it has proved efficacious in the observation period of six months.