Distraction osteogenesis(DO) can be performed in the bony defect associated with trauma, anomaly, and various kinds of disease. The gap generated by DO is filled with growing callus : during the period of distraction, the osteogenesis is continued. However, there have been few reports about expression pattern of growth factors in newly formed bone during the consolidation periods. We performed DO in the mandibular defect case and studied the expressed pattern of growth factors. Its pattern was compared to that of the same patient. BMP-2 and -4 were strongly expressed in the DO site. Particularly, BMP-4 was not expressed in the normal mature bone, but expressed in new bone in DO. However, there was no difference in the FGF-7 expression between the sites. Therefore, strong expression of BMP-4 are related to new bone formation in DO and they may not be related to the normal homeostasis in human bone. Though FGF-7 is related to the growth of keratinocyte, it may have minimal role in the DO and normal mature bone.