With the development of craniofacial surgery, today sagittal split mandibular osteotomies are frequently used for file treatment of mandibular deformities with modifications and different fixation techniques. In clinics, 57 patients are evaluated ill this study. Of these patients, 35 were male, 22 were female, and their ages were between 17 and 47 years (oil average, it was 23 years). Thirty-seven of these patients were treated with bilateral sagittal split mandibular osteotomy (SSMO), 12 of them with unilateral SSMO. 6 of them with bilateral SSMO + Le Fort I osteotomy. and 2 of them,with bilateral SSMO + Le Fort 11 osteotomy. Orthodontic treatment modalities were performed for 8 patients preoperatively and to all of the patients postoperatively. All patients were examined with cephalometric analysis preoperatively and postoperatively. Internal and external distractors were applied for 14 patients. Rigid fixation with plates and screws was done for 21 patients. Fixation with screws for 5 patients, fixation with wires for 3 patients. and intermaxillary fixation for 8 patients were performed. Patients were followed up oil average 13 months (6-22 months). In I patient, infection on the osteotomy line and recurrency developed. Sensory area of the alveolar nerve became normal in 10 to 16 weeks usually, but in 3 patients, sensory loss developed at this region. Complaints of temporomandibular joint dysfunction developed in I patient at the third postoperative month. When the clinical use was determined. we observed that SSMO Could give satisfactory results ill selected patients with mandibular deformities. Dental structures are important in relation to the postoperative occlusion and masticatory functions, for this reason,,we think that postoperative orthodontic treatment will be useful for these patients.