Background and Purposes: Orthognathic surgery is necessary in more than 25% of patients with cleft lip and palate (CLP) to correct skeletal discrepancy and to obtain harmonious facial esthetics in the final phase treatment. A setback of mandible by bilateral sagittal split osteotomy (BSSO) along with maxillary osteotomy is usually performed when large skeletal discrepancies or associated mandibular deformities (e.g., asymmetries, canting of the mandibular occlusal plane) are present. Although the surgical technique of BSSO is well-developed, the neurosensory disturbances of the inferior alveolar nerve (IAN) remain one of the major postoperative complications. The purpose of this study is to identify the risk factors of IAN disturbances after BSSO and in turn to help clinicians to avoid such complication and to raise the satisfaction level of patients.