Zoledronic acid, a potent nitrogen-containing bisphosphonate, plays a key role in preventing complications of bone metastases in metastatic breast cancer, but its affect on early-stage breast cancer has been unclear. The preclinical data supporting the anticancer effects of zoledronic acid are compelling and several recent clinical trials have suggested that it reduces breast cancer recurrence in certain patient subgroups. Given these anticancer effects and reasonable safety profile, this therapeutic option could be discussed with patients. This article focuses on the results of supporting preclinical and clinical data evaluating the role of zoledronic acid in adjuvant breast cancer therapy.