A female patient of fifteen years old with anterior crossbite was treated orthodontically with multi-bracket system. During the orthodontic treatment clicking and trismus were appeared. According to the consultation, it was found that the TMJ disorder was in the stage of the closed lock. The patient was treated with the manipulation technique and the anterior repositioning appliance was applied. After three months, the pain and trismus were relieved. The maxillary arch was expanded laterally to eliminate the premature contact caused by the maxillary and mandibular canines. Consequently, intercanine width of the maxillary arch was increased and the cuspal interference was disappeared. After three month observation, it seemed that the symptoms of TMJ were recovered. Then, orthodontic appliances were removed and the retainers were set. It was concluded that the examination of TMJ condition may be necessary for orthodontic patients with anterior crossbites.