PURPOSE: To evaluation of usefulness of low-intensity ultrasound for nonunion and delayed union. MATERIALS AND METHODS: For 5 months, we treated 7 delayed union and 8 nonunion using low-intensity ultrasound. After 5 months, in checked X-ray AP and Lateral view, when cortical bridge formation was done, we through union. RESULTS: In 7 delayed union, 5 cases-2 femur, tibia, humerus, radius were healed. In 8 nonunion, 3 femur nonunion were healed. Union rate was 71% in delayed union 37.5% in nonunion. CONCLUSION: we thought that the low-intensity ultrasound has capacity of induction of union and was considered as the method of treatment for delayed union.