Purpose: A prospective consecutive case series study was performed during the period between December 2014 and July 2017, aimed to evaluate the effectiveness of the use of injectable platelet rich fibrin (PRF) in the treatment of tempromandibular joint hypermobility. Patients and methods: Twelve patients suffering from TMJ hypermobility were treated by PRF intra articular injection twice with one month interval. Patients underwent clinical investigation with complete assessment of pain, frequency of dislocation, range of motion and TMJ sounds, this was preformed pretreatment then on first, third, sixth, and ninth months post treatment. Pre and post radiological CBCT was performed to assess the degree of capsular and ligamental laxity (DCLL), and the Condylar position (CP) at maximum range of motion. Results: The results of the study showed that PRF had a highly significant positive effect on the clinical signs and symptoms of TMJ hypermobility over the first 6 months postoperatively, but at 9 months, the results were not sustained on the same clinical improvement level. Conclusion: The injection of PRF is an effective, minimally invasive method that could be used for treatment of TMJ hypermobility by improving capsular and ligamental integrity. Additionally, it significantly improves all signs and symptoms up to 6 months since the TMJ injection, so it is recommended to repeat the procedure yearly.