Rosai-Dorfman disease (RDD) is a rare disorder, often benign but with possible life-threatening prognosis. In most cases, specific treatment is not necessary; when required, the management of RDD is not codified to date, and various chemotherapies have been shown to be ineffective. Here, we report a patient with RDD who presented a dramatic and sustained response with cladribine. Analysis of the cytokine profile evolution shows a clear correlation between serum levels of TNF-alpha and IL-6 and disease activity. Our findings show the promising efficacy of cladribine and suggest that therapies targeting specifically cytokines might be useful in some cases of active RDD.