Bisphosphonate-associated osteonecrosis of the jaw (BON) is mainly observed in patients with multiple myeloma, and to a lesser extent in breast and prostate cancer patients receiving intravenous treatment with potent bisphosphonates. The incidence of BON increases with the duration of bisphosphonate therapy and with the potency of the used bisphosphonate. BON usually develops after tooth extraction or other oral surgery, and has proven difficult to treat. Optimal dental hygiene should be ensured prior to treatment initiation where possible, and once bisphosphonate treatment is instituted, oral surgery should be avoided if possible.