It has been demonstrated that bisphosphonate-based supportive therapy (pamidronate or zoledronate) reduces skeletal events (onset or progression of osteolytic lesions) both in patients with multiple myeloma (MM) and in cancer patients with bone metastasis. Bisphosphonates (eg, alendronate) are also indicated in the treatment of osteoporosis. Nevertheless, osteonecrosis of the jaw (ONJ) has been reported in some patients being treated with bisphosphonates. We present a series of 9 MM patients who developed ONJ after treatment with bisphosphonates and chemotherapy. All the patients in this case series had undergone tooth extraction for recurrent dental abscesses while taking bisphosphonates. We also review the diagnostic and therapeutic implications of this paradoxical complication associated with treatment of bone lesions in MM.