Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is a severe bone disease for which the pathogenetic mechanisms and risk factors are not fully understood. The present study evaluated the data of 652 patients with bone metastasis that had undergone treatment with biphosphonates. Subsequently, 24 patients with BRONJ and 20 control patients without BRONJ that were treated with zoledronic acid were enrolled. It was found that BRONJ occurred in 3.6% of patients. The mean age and the administration of dental treatment were found to be significantly associated with BRONJ development (P=0.049 and P=0.013, respectively). The cumulative dose median in the BRONJ group was found to be significantly higher compared with the cumulative dose average in the control group (P=0.037). In addition, at the time of BRONJ development, improvement in the disease was determined to be better in the BRONJ group than in the control group (P=0.031). The present study determined that age, the existence of dental extraction and the cumulative dose of zoledronate were all important risk factors in BRONJ development.