Goldenhar syndrome is a well-known condition featuring the following triad of anomalies: ocular abnormalities, microtia and vertebral anomalies. This syndrome involves structures arising from the first and second branchial arches. Craniofacial anomalies, including mandibular, zygomatic and/or maxillary hypoplasias are found in 50% of patients with Goldenhar syndrome. Patients with this syndrome may present unilateral or bilateral underdevelopment of the mandible. Several treatments for the correction of the dento-facial deformity have been described, among them distraction osteogenesis is one that shows promising results. Distraction osteogenesis is the process of bone formation that occurs during slow separation of the segments of bone after an osteotomy and it has been used to alleviate facial asymmetry. Mandibular distraction osteogenesis has been applied for many years, but long-term reports present controversial results. The purpose of the case report is to describe the immediate and long-term effects of distraction osteogenesis used to treat mandible asymmetry in a 5-year-old boy with Goldenhar syndrome.