An 80-year-old Japanese woman with temporal arteritis was treated with systemic recombinant human interleukin-2 (IL-2) (1 x 10(6) unit/day for six weeks). The presenting symptoms of headache and skin necrosis and abnormal laboratory findings, such as an elevated erythrocyte sedimentation rate and CRP, promptly improved without any serious side effects. Although the pathogenesis of temporal arteritis and the mechanism(s) of the beneficial effect of IL-2 on it still remain unknown, this preliminary study highly encourages further investigations.