Seventy-five patients were studied retrospectively to assess the prevalence and variance of temporomandibular dysfunction in an orthognathic surgery population. Preoperatively, 49.3% of the sample presented with temporomand ibular dysfunction. After orthognathic surgery, of the symptomatic patients, 89.1% had improved temporomandibular function after surgery, 2.7% were unchanged, and 8.1% had increased symptoms. Of the patients asymptomatic prior to surgery, 7.9% developed temporomandibular dysfunction postoperatively. Temporomandibular dysfunction was significantly more prevalent in patients with a Class II skeletal deformity than in those with a Class III deformity, and temporomandibular function generally improved in both groups postsurgically.