Distraction osteogenesis has been widely utilized to treat leg length discrepancy, deformity, nonunion, osteomyelitis, and bone loss. It has been found that most difficult conditions can be resolved with this method. This paper introduces the usefulness of distraction osteogenesis for the treatment of nonunion and bone loss after tumor excision. The procedure was found to be extremely effective for the treatment of nonunion accompanied by bone loss and infected nonunion. In particular, the Ilizarov method offers a simultaneous solution for several problems related to nonunion, such as instability, infection, deformity, bone loss, joint contracture, limb length discrepancy, and skin defects. In addition, distraction osteogenesis is safe, useful, and efficient for the treatment of bone loss even after tumor excision. Joint preservation and reconstruction by means of distraction osteogenesis is the most conservative limb-saving surgery available at present. Furthermore, distraction osteogenesis can provide natural limb regeneration.