Takayasu's arteritis (TA) is a chronic idiopathic inflammatory disease affecting primarily aorta and its proximal branches. Pediatric patients with TA tend to have more severe clinical course and be refractory to conventional treatments compared with adults. Corticosteroids are major treatment of TA, however, high dose is required to get remission. Particularly, adolescent patients are usually suffering from side-effects of excessive dose of corticosteroids. Immunosuppressants are added expecting the corticosteroid sparing agents. However, some patients, such as HLA-B52 positive, tend to be registant to these conventional treatments. Recently, several reports showed the efficacy of Infliximab, anti-tumor necrosis factor (TNF) alpha monoclonal antibody, for adult patients with refractory TA. We described three cases of adolescents with TA treated with Infliximab. It was initially effective in all three patients. However, serious infusion reaction occurred in one of them during 11(th) times of Infliximab infusion and she discontinued the therapy. Other two patients showed good response in initial phase, but clinical manifestations and laboratory findings became worse after several months. In these patients with secondary failure to Infliximab, increased dosage and shortening the interval of infusions provided effectiveness again. Infliximab would be a good choice for adolescent patients with TA refractory to conventional treatments. However, we should carefully monitor safety and efficacy of this agent considering its peculiarity.