Tocilizumab is an anti-interleukin (IL)-6 receptor monoclonal antibody, used since 2010 for the treatment of severe rheumatoid arthritis (RA). It is known to induce infection, similarly to other biotherapies which modulate immune response and cytokines. Few cases of malignancy, however, have as yet been reported. We describe here the case of a patient with severe RA, previously treated with prednisolone, methotrexate, leflunomide, etanercept, and rituximab, who, after 8 months of treatment with tocilizumab, developed rapidly progressive nodular melanoma on a preexisting pigmented lesion on her left cheek. Recently, another case of nodular melanoma under tocilizumab has been published. The possible causative role of tocilizumab and other immunomodulatory agents in the development of this malignancy is discussed. Based on the present case, dermatologic screening is recommended before initiation of tocilizumab.