We report a case of osteonecrosis of the jaw in association with bisphosphonate treatment for bone metastases from breast cancer that developed seven months later after the last cycle of zoledronate. An 81-year-old woman underwent modified radical mastectomy for right breast cancer in June 2001. She received tamoxifen for postoperative adjuvant therapy. Bone metastases developed in December 2001 and she received several kinds of chemoendocrine therapy until June 2004, at which time treatment was discontinued due to adverse reactions. As metastatic progression of the disease was observed, treatment with pamidronate and tamoxifen was initiated in September 2004. Pamidronate was changed to zoredoronate in June 2006. In January 2007, two teeth were extracted due to periodontitis and zoledronate was discontinued. Zoledronate treatment was resumed from March 2007 ; however it was stopped again because of renal dysfunction in July 2007. The patient complained of continuous mandibular pain in February 2008, at which time a diagnosis of osteonecrosis of the jaw was made. Given the long half-life of these drugs, osteonecrosis of the jaw can remain a potential complication for years after bisphosphonate therapy. Therefore, patients should be counseled to receive regular follow-up with a dentist after treatment with bisphosphonates.