Purpose: This study evaluated the prognosis of conservative and surgical treatment according to the staging of bisphosphonate-related osteonecrosis of jaw (BRONJ) by American Association of Oral and Maxillofacial Surgeons and American Society for Bone and Mineral Research. Methods: We evaluated 53 patients of BRONJ who visited Department of Dentistry, Ajou University School of Medicine from May 2007 to February 2013. Twenty eight patients in stage 2, were divided into surgical and conservative groups with cessation of bisphosphonate therapy. Fifteen patients belonged to the conservative treatment group, in which mouth rinsing and antibiotics medication were done. Thirteen patients were treated with debridement or sequestrectomy, in the surgical treatment group. Each study list was analyzed by SPSS ver. 14.0 (SPSS Inc., USA) software and the favorable rate was verified by the Fisher exact test. P-values less than 0.05% were deemed significant. Results: Clinical outcome was evaluated on the basis of both clinical and radiographic findings. Of all the 28 patients of stage 2, 15 patients underwent conservative treatment and 13 patients received surgical treatment. In the surgical group, 9 of 13 (69.2%) showed good prognosis, 4 of 13 (30.7%) showed recurrence. In the conservative group, 13 of 15 (86.6%) showed no change duting the follow-up period. Two of 15 patients even showed a bad prognosis, such as pain and pus discharge, which are criteria for stage 3. P-value was 0.067 (>0.05). Conclusion: The results of the present study suggests that surgical intervention is good choice against the conservative treatment, after proper drug holidays period, while further investigation is needed for a definite solution to BRONJ.