This is the first report on the efficacy of leukocytapheresis (LCAP) in a patient with refractory systemic-type adult-onset Still's disease (AOSD). A 17-year-old Japanese woman with AOSD who had been treated with prednisolone and cyclosporine A presented with relapse of typical systemic AOSD, including high fever, rash, and liver dysfunction. Steroid pulse therapy (methylprednisolone 500 mg/day) was performed, which failed to stabilize the disease. Therefore, LCAP (twice/week for a total of five courses) was introduced in combination with high-dose steroids plus cyclosporin A. Elevated levels of serum ferritin and transaminases and neutrophil CD64 expression normalized after the patient's disease was successfully controlled by the induction of LCAP. In this case, elevated levels of interleukin (IL)-1β and IL-18 were normalized after LCAP induction, suggesting that LCAP treatment modulates the deregulated cytokine-mediated inflammatory responses observed in AOSD. Our clinical observations suggest that LCAP may be beneficial for flare-up of systemic manifestations of AOSD refractory to conventional treatment, including high-dose steroids and immunosuppressants.