The treatment of temporomandibular joint ankylosis requires excision of the involved structures and immediate reconstruction. This paper presents a consecutive series of nine pediatric patients (mean age 7.7 years) who underwent a standardized treatment protocol to 13 affected joints. Four patients had unilateral temporomandibular joint ankylosis, five bilateral. One child required bilateral release but only unilateral reconstruction. Radiographic evidence demonstrated bony ankylosis in a total of 13 joints. Two patients had undergone surgical intervention of the temporomandibular joint before presentation to the authors. Two patients had preoperative temporomandibular joint pain. The cause of ankylosis was primarily traumatic or congenital. Our operative protocol included excision of the involved ankylotic structures through a coronal and Risdon incision, followed by immediate costochondral grafting. Fixation with miniplates and screws allowed for early mobilization. For unilateral patients, maximal incisal opening was improved from 5.4 mm before surgery to 24.8 mm after it, and for bilateral patients, from 6.0 to 17.5 mm. Mean follow-up was 2 years; only one patient was followed for less than 1 year. Pain symptoms were relieved after surgery. Perioperative complications were minimal, with no evidence of infection, facial nerve injuries, or bleeding. Patients with unilateral or bilateral ankylosis of traumatic cause achieved satisfactory functional results after surgery, while those in our bilateral congenital patients were far more limited. Rationales for this divergence in results are presented.