Introduction:  TMJ internal derangement is characterized by intra-articular disc displacement resulting in popping or clicking sounds. The displacement of articular disc does not always cause a mechanical obstruction. Those conditions may be with or without pain. Aim: The aim of the study was to evaluate the clinical effect of intra-articular injections of platelet rich plasma for management of TMJ internal derangement through comparative study with dextrose prolotherapy. Patients and Methods: included 87 joints in 45 adult patients complaining pain, clicking in the Temporo-mandibular joint (internal derangement), pre-operative MRI was done for all patients with further clinical, radiographic as well as TMJ examination. Patients were divided into three equal groups randomly. Group I: (study group) composed of 15 patients where 1ml of platelet rich plasma was injected intra-articular (once) Group II: (study group) composed of 15 patients where 1ml of platelet rich plasma was injected intra-articular (twice) with one month interval Group III: (control group) composed of 15 patients where dextrose prolotherapy was injected (4 times) at 2 weeks, 4 weeks and 6 weeks intervals over a total of 12 weeks. Clinical assessment was done including MIO, pain, deviation and clicking. Results: statistically analysis of this study showed that group I, III showed the highest MIO values as well as VAS scores in the 3,6 and 12 months, however group II showed the lowest MIO in the same follow up period. Conclusions: PRP and Prolotherapy are successful techniques for treatment of symptoms related to internal derangement of TMJ.