Rituximab, an anti-CD20 monoclonal antibody, is an effective treatment for rheumatoid arthritis. Here we report the case of a patient with rheumatoid arthritis, having taken risedronate for 14 months to prevent corticosteroid-induced osteoporosis, more than 2 years ago, who presented osteonecrosis of jaw following herpetic gingivostomatitis two weeks after the beginning of a rituximab treatment associated with her usual anti-rheumatic drugs. Eight weeks later, no bone and/or gum healing was observed and a stage 2 medication-related osteonecrosis of the jaw (MRONJ) was diagnosed. A conservative approach was decided with antiseptic mouth washes, low-level laser treatment (LLLT) and systemic therapy with teriparatide. Complete mucosal coverage was obtained after more two years of follow-up. We suggest that rituximab as immunosuppressant might be a cause or a decompensating factor of MRONJ. Non-surgical periodontal treatment with LLLT and teriparatide are candidates for the treatment of MRONJ.