TMJ ankylosis is defined as a mobile disorder of jaw such as mouth opening limitation, limitation of anterior or/and lateral movement of TMJ. Kazanjian published first clinical report about classification of TMJ ankylosis dividing with intracapsular ankylosis and extracapsular ankylosis. TMJ ankylosis is resulted from trauma, infection, metastatic tumor, irradiation, burn and etc. When TMJ ankylosis is manifested in growing period, it affects to functional disorder and development and position of mandible, so it can result in maxillofacial deformity such as facial asymmetry, micrognathia, malocclusion. For treatment of TMJ ankylosis, various surgical interventions were devised; condylectomy, gap arthroplasty, interpositional arthroplasty and TMJ reconstruction. So, we report our results with documental study and cases of true ankylosis in our department.