1178 patients with mandibular prognathism and/or asymmetry, in some cases combined with maxillary retrognathism, were treated by extraoral horizontal or oblique ramus osteotomy during the period from 1939 to 1989. The described percutaneous retromandibular approach is a simple, rapid and reliable technique which can usually be performed under local anaesthesia. Very few complications, particularly neurological, were observed. These aspects justify consideration of this technique when indications for a simple, straight set-back procedure of the mandible exist, and there is no tendency to bite-opening. However, the method demands intermaxillary fixation for 6-9 weeks postoperatively.