Purpose: The effect of orthognathic surgery on the temporomandibular dysfunction has been controversial. The purpose of this study is to prove statistically that early removal of fixation plate at postoperative 2 weeks with active exercise of mouth opening could relieve preoperative temporomandibular dysfunction and reposition of temporomandibular joint. Patients and Methods: All 28 subject patients underwent mandibular setback with BSSRO in Kyunghee medical center by one surgeon. The fixation plates used for rigid fixation were removed at postoperative 2 weeks and we had the patients excercise active mouth opening with intermaxillary rubber rings for the guiding proper postoperative occlusion. Temporomandibular symptoms were checked and radiographs were taken before surgery, within a month after surgery, six to twelve months after surgery respectively. Results: The temporomandibular dysfunction symptoms were relieved after the surgery and the condyle was displaced inferior-posteriorly immediate after surgery and repositioned toward its original position during follow-up periods. Conculusion: Orthognathic surgery may benefit temporomandibular joint dysfunction by obtaining a postoperative stable occlusion and more physiologic neuromuscular function. The early removal of fixation plates after BSSRO could reposition the temporomandibular joint to physiologic position and relieve the symptoms of temporomandibular dysfunction by permitting movement of proximal segment.