Introduction: Temporomandibular joint (TMJ) ankylosis is an extremely disabling affliction that causes problems in mastication, digestion, speech, appearance, and hygiene. Objective: Report a case of TMJ ankylosis diagnosed in adulthood and discusses the aspects involved in their treatment, and the use of temporal muscle flap in reconstructive surgery of the TMJ. Cases description: 39 year-old female with mouth opening of 4mm, was diagnosed with left TMJ ankylosis and treated by arthroplasty with interpositional temporalis muscle flap, progressing with mouth opening of 20 mm after two months out surgery. Conclusion: Despite the numerous surgical techniques for the treatment of TMJ ankylosis, it is still a great challenge, because of high rates of recurrence, which is associated with several factors including age, time of onset, surgical technique, and postoperative care performed. Therefore, it is necessary not only an interdisciplinary team to establish a complete and adequate treatment, but also to carry out a correct and early diagnosis in order to establish a treatment the prognosis is favorable to the patient.