Introduction: The incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ) has increased gradually in patients who have undergone surgical treatment for osteomyelitis. In this study, a retrospective analysis of BRONJ patients was carried out using the data of osteomyelitis patients treated surgically. Materials and Methods: Osteomyelitis patients, who underwent curettage, sequestrectomy, saucerization or decortications, and partial mandibulectomy at Seoul National University Dental Hospital from 2004 to 2010 were enrolled in this study. The patients were classified and categorized into two groups based on the surgical records and progress notes. One group comprised of patients with osteomyelitis and osteoporosis, and the other group included patients with osteomyelitis only. The epidemiological data of the BRONJ patients was analyzed to identify any trend in the incidence of BRONJ in osteomyelitis patients. Results: Among 200 patients who underwent surgical intervention for osteomyelitis, 64 (32.0%) were identified as having osteoporosis as the underlying disease. In these 64 patients, more than 81.3% had been prescribed bisphosphonates. Females were far more affected by BRONJ than males. The incidence of BRONJ also increased with age. The posterior part of the mandible was affected more frequently by BRONJ. Conclusion: Although the availability of potent antibiotics and increased oral hygiene care can reduce the overall incidence of osteomyelitis, BRONJ can increase the total incidence. To prevent BRONJ, it is recommended that an oral examination be performed before prescribing bisphosphonates. Moreover, the patients should be educated about the potential risks of dental procedures that might be causal factors for BRONJ. Furthermore, patient swho take bisphosphonates for the treatment of osteoporosis should undergo periodic follow up oral examinations to prevent BRONJ.