Jaw bone necrosis is a clinical condition associated with defects in vascularization of the maxilla or the mandibular bone, usually present following head and neck radiotherapy and/or oral surgical interventions. Bisphosphonates are synthetic analogues of pyrophosphate used in the treatment of patients with hypercalcemia as a result of malignancy, bone metastasis and for the treatment of other disorders such as metabolic bone diseases, Paget's disease and osteoporosis. Over last 10 years, cases of jaw bone necrosis have been associated with the use of bisphosphonate therapy. In particular, Ruggiero et al. (J Oral Maxillofac Surg 2004; 62: 527-534) in 2004 described a large group of patients (63) with jaw bone necrosis probably related to the use of these drugs. It should be noted that all the patients in the group described either underwent head and neck radiotherapy or had a dental extraction while taking bisphosphonates. In the present study, we reported four cases of jawbone necrosis in patients taking pamidronate (Aredia) and zoledronate (Zometa) without having undergone any kind of radiotherapy or dental surgery. All the patients were females between the ages of 56 and 71 years; three were treated with bisphosphonates for bone metastasis and one for multiple myeloma. All the patients received surgical treatment with bone curettage, with partial and/or temporary improvement of the lesions. Although a treatment for bisphosphonate-induced bone lesions has not yet been established, we suggest careful evaluation of the patients' oral health before prescribing bisphosphonate treatment.