Abstract We report the case of a 56-year-old Japanese woman with Behçet's disease and myelodysplastic syndrome (MDS), who had a history of episodic high-grade fever, recurrent oral and genital ulcers, and erythema nodosum, during a 13-year period from 1989 to 2002. Bone marrow aspirates obtained in January 1995 showed refractory anemia with trisomy 8, a subtype of MDS. Her serum levels of soluble interleukin-2 receptor (IL-2R), interferon-γ, IL-1β, IL-6, IL-8, and granulocyte-macrophage colony stimulating factor in the active state were higher than those in the inactive state, whereas those of tumor necrosis factor-α and IL-10 did not increase even in the active state. In this case, it was speculated that a T-cell immune response might have been involved in the disease pathogenesis, and that the repeated febrile episodes might have been a manifestation of neutrophil hyperfunction induced by increased serum levels of inflammatory cytokines.