PURPOSE: Osteonecrosis of the jaw (ONJ) is a devastating side effect of long-term bisphosphonate (BP) use. We present the largest case series from a single department. MATERIALS AND METHODS: This case series included 101 ONJ patients. Data on demographics, medical background, type and duration of BP use, possible triggering events, mode of therapy, and outcome were recorded. RESULTS: ONJ was associated with intravenous BPs in 85 patients and with oral BPs in 16 patients. It was diagnosed after 48, 27, and 67 months of pamidronate, zoledronic acid, and alendronate use, respectively. Long-term antibiotics and minimal surgical procedures resulted in complete or partial healing in 18% and 52% of the patients, respectively; 30% had no response. There was no association between ONJ and diabetes, steroid and antiangiogenic treatment, or underlying periodontal disease. Diagnostic biopsies aggravated lesions without being informative about pathogenesis. A conservative regimen is our treatment of choice. CONCLUSION: Solutions for decreasing morbidity and poor outcome of ONJ remain elusive.