The development of surgical correction of class III cases in recent years has made it more interesting for the orthodontist to handle mandibular prognathism. Treatment of patients in this classification is really just coming to the fore, and represents a closer cooperation between two fields of specialization, oral surgery and orthodontics. Setback of the mandible to correct mandibular prognathism is a well known procedure. The 2 most frequently used techniques are the intraoral vertical ramus osteotomy (IVRO) and the sagittal split ramus osteotomy (SSRO). In our patient we successfully used the SSRO procedure to correct mandible prognathism. The duration of treatment is of 10 months, and the prognathic profile had been improved and the anterior cross bite been relieved with finishing the occlusion in the cusp-fossa (class II) relationship.