Objective : Recently, we are interested in bisphosphonate related osteonecrosis of the jaw (BRONJ). Most of patients with osteonecrosis have taken medicine bisphosphonate for a long time. But the mechanism of osteonecrosis in BRONJ was not clarified yet. The aim of this study is to evaluate the difference of bone healing effect after bone graft from ilium to maxillary sinus in rabbits between zoledronate-treated and zoledronate-not treated groups. Method : The subjects was divided into two groups. The experimental group was 9 rabbits, treated with intraperitoneal administration of zoledronate(0.06mg/kg) once per week for 3 weeks. In control group, same procedure was applied but administerd saline instead of zoledronate. After 4 weeks, surgical operation under local anesthesia (ketamine 3.0cc, xylazine 1.0cc) was done. At postoperative 1, 2, 4, 8 weeks later, each rabbits were sacrificed and removed the bone grafted area. Gross, radiologic and histopathologic exminations of bone grafted area were performed. Result : There were no conspicuous differences of radiological findings between experimental and control groups in any experimental weeks. In experimental group, new bone formation appeared earlier than control group at 1 week after operation, and maturation of bony tissue were more conspicuous at 2 and 4 weeks after operation, compared with control group. In 8 weeks after operation, similar microscopic findings were noted in both groups. Conclusion : In the bisphosphonate-treated rabbits, new bone formation in the bone grafted area appeared earlier and bony maturation was more concpicuous, even though there were no significant differences of gross and radiological findings. These findings suggest that bisphosphonate might be promotive effect in the healing process in early stage after administration.