Sixty four patients were followed-up for over 6 months following the orthognathic surgeries and were examined for the Temporo-mandibular joint dysfunction. The results are as follows: 1. Of 64 patients, 9(14.1%) had been suffered from TMD preoperatively : 4.7% in the prognathism and 46.2% in the laterognathism. 2. Following the orthognathic surgeries, 7 of 64 patients(10.9%) complained TMD, and 55.6% of the TMD patients resulted in significant improvement. 3. By the type of deformities, laterognathism with TMD could be expected to be improved in 30.8%, while 7.7% in the prognathism. 4. Non-rigid fixation resulted in higher incidence of TMD than the Rigid fixation after the SSRO ; 4 of 15(26.5%) and 2 of 25(8.0%) respectively.