Purpose: The aim of this study was to investigate the effect of the autologous blood injection (ABI) for chronic recurrent temporomandibular joint (TMJ) dislocation using magnetic resonance imaging (MRI). Materials and Methods: ABI was applied to 14 patients who had chronic recurrent TMJ dislocation. MRIs of the patients were taken and compared before and one month after the injection. Results: All of the patients had no dislocations of their TMJs on clinical examination one month after the injection. In the pre-injection, unilateral or bilateral TMJ dislocations were observed on MRIs in all patients. One month after the injection, TMJ dislocations were not observed in MRI evaluation of any patients. A significant structural change that caused by ABI was not observed. Conclusion: The procedure was easy to perform and it caused no foreign body reaction. However, it was unclear how the procedure prevented the dislocation. © 2012 by Korean Academy of Oral and Maxillofacial Radiology.