Purpose: The aim of the present study was to evaluate intraoperative and postoperative complications associated with bilateral sagittal split osteotomy (BSSO), and to analyse whether complications were associated with age at operation and patient’s satisfaction with the result. An additional objective was to analyse whether nerve damage during surgery was related to persistent neurosensory disturbance in the facial skin. Sample: 132 patients with skeletal Class II malocclusion operated between 1990 and 2002 with BSSO for advancement of the mandible participated in the study. Surgery was performed at Department of Maxillofacial Surgery Ullevaal University Hospital, and all subjects were followed for 3 years at Department of Orthodontics, University of Oslo. Methods: Intra- and postoperative complications were assessed from the medical records. Neurosensory function and patient’s satisfaction with outcome were assessed from clinical examination and patient’s response in questionnaires 3 years after surgery. Associations between variables were analyzed by Chi square test, Fisher exact test or t- test.Results and Conclusions: The inferior alveolar nerve was inadvertently injured in 36 sides (14%), suboptimal splits occurred in 15 sides (6% of the sides, 11% of the patients), 18 patients (14%) experienced postoperative infection, and osteosynthesis was removed in 10 patients (8%). Three years after operation, 76% of the patients reported not having normal sensation and 15% reported the alterations in sensibility to be distressing during daily life. Age had no significant effect on the prevalence of complications with exception of distress related to sensory disturbance. Dissatisfaction tended to increase among patients experiencing complications, but the only statistically significant relationship was observed among subjects reporting distress because of their altered sensation. Registration of visible nerve injury during surgery was significantly reflected in the degree of neurosensory disturbances.