This study investigated the prevalence of temporomandibular disorder (TMD) among patients before and after orthognathic surgery and assessed the effect of orthognathic surgery on each of the TMD symptoms (clicking, pain, crepitus, and MRI findings). A sample of 100 consecutive patients undergoing bimaxillary surgery for correction of craniofacial deformities (31 male and 69 female), with ages ranging between 17 and 58 years (mean age: 27.7 ± 9.3 years), were interviewed and examined regarding signs and symptoms of TMD. Clinical examination and X-ray and magnetic resonance imaging of the temporomandibular junction were performed at the time of surgery and 1 year thereafter. The prevalence of TMD preoperatively and postoperatively was 35% and 27%, respectively. A high frequency of relief was found in the patients with TMD symptoms (74.3%; 19 (70.3%) of patients had reduced clicking, 7 (87.5%) patients had reduced pain, 4 (100%) patients had reduced crepitus, and 4 (57.1%) patients showed changes in MRI findings), 12 patients who were asymptomatic before surgery developed clicking in TMJ after surgery, 3 developed pain, and 3 developed crepitus. TMD problems can occur in a variety of patients, including those who have facial deformities, and require orthognathic surgery. However, orthognathic surgery may not predictably treat or reduce the symptoms of TMD.