Alveolar distraction is being used increasingly for alveolar bone reconstruction in patients with severe mandibular defects. When there has been total loss of alveolar bone, distraction of the mandibular basal bone is necessary. Distraction osteogenesis is considerably more challenging in mandibular basal bone than in alveolar bone. The low level of the cut increases the technical difficulty and may result in a poor outcome. We describe three cases in which more than 10 mm of distraction of mandibular basal bone was required. Semirigid distraction devices were used to reconstruct the alveolar structures in each case. (C) 2002 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved.