To study the effects of combined surgical-orthodontic treatment, recordings of functional and border movements were obtained before and after surgery for 16 patients with severe skeletal malocclusions. The tracings showed a clear difference in the functional adaptation to mandibular setback and mandibular advancement surgeries. Patients with a skeletal Class III malocclusion who had undergone mandibular setback surgery generally showed an increase in the range of border and masticatory movements postsurgically. Patients with a skeletal Class II malocclusion corrected by mandibular advancement showed a restricted range of motion immediately postoperatively. Even 12 months after surgery, their recordings did not completely appraoch presurgical values.