Background: Disc derangement disorders of the TMJ are a group of intra-articular biomechanical disorders in which there is an abnormal relationship in the functional 'articular cartilaginous' condyle-disc complex. Platelet-rich plasma (PRP) is a blood product that allows in a simple, low cost, and minimally invasive way to obtain a concentration of many growth factors when activated. Aim: To compare the use of arthrocentesis alone and arthrocentesis in addition with platelet rich plasma in management of TMJ internal derangement. Materials and Methods: fourteen patients with DDwOR were included in the study diagnosed according to The Research Diagnostic Criteria for Temporomandibular disorders (RDC/TMD) and divided into two groups as follow; seven patients underwent intra-articular injections of 2 ml PRP after arthrocentesis (study group) and the other seven patients were treated by the conventional arthrocentesis using Ringer's solution (control group). The patients were clinically evaluated preoperatively and postoperatively at the intervals of 1 month and 6 months. Results: The differences between the two groups in all the measured parameters were statistically insignificant throughout the postoperative period. Conclusion: injection is a safe and effective method in the treatment of TMDs.