Antiresorptive osteonecrosis of the jaws (ARONJ) is a significant and poorly understood oral complication that may affect patients receiving antiresorptive agents, such as intravenous bisphosphonate therapy. There are scarce reports of the coexistence of ARONJ and metastasis at the same jaw site in the English-language literature. In the present case, a 60-year-old white woman was referred for the evaluation of a nonhealing extraction socket. The patient was undergoing treatment with intravenous zoledronic acid to metastatic breast cancer in bone, and her medical history and clinical characteristics led to the diagnosis of ARONJ. Nevertheless, histologic analysis showed a fragment of necrotic bone and bacterial colonies associated with malignant epithelial cells that were confirmed to be metastatic breast adenocarcinoma. This case showed that jaw metastasis can occur at the same time and site of ARONJ, making diagnosis and management challenging.