Objective. Granulomatous inflammation is a typical feature of Takayasu arteritis (TA), and tumor necrosis factor (TNF) is important in the formation of granulomas. In this study, we assessed therapy with anti-TNF agents in patients with TA that was not controlled by glucocorticoid therapy or other immunosuppressants. Methods. We conducted an open-label trial of anti-TNF therapy at 3 academic medical centers over a period of 4.25 years. Fifteen patients with active, relapsing TA (median 6 years) were selected. Seven received etanercept (later changed to infliximab in 3 patients), and 8 received infliximab. Relapses had occurred in all patients while they were receiving glucocorticoids and, in 13 patients, additional immunosuppressive drugs. No other agents were added to the treatment regimen concurrently with anti-TNF. If patients were receiving cytotoxic agents, the dosage was not increased. Clinical symptoms were recorded, and physical examinations, laboratory studies, and serial magnetic resonance imaging were performed. Results. The median daily dose of prednisone required to maintain remission prior to anti-TNF therapy was 20 mg. Ten of the 15 patients achieved complete remission that was sustained for 1-3.3 years without glucocorticoid therapy. Four patients achieved partial remission, with a >50% reduction in the glucocorticoid requirement. At a median of 12 months of followup, the median dose of prednisone was 0. Therapy failed in 1 patient. In 9 of the 14 responders, an increase in the anti-TNF dosage was required to sustain remission. Two relapses occurred during periods when anti-TNF therapy (etanercept) was interrupted, but remission was reestablished upon reinstitution of therapy. Conclusion. In this pilot study of relapsing TA, addition of anti-TNF therapy resulted in improvement in 14 of 15 patients and sustained remission in 10 of 15 patients, who were able to discontinue glucocorticoid therapy. Anti-TNF may be a useful adjunct to glucocorticoids in the treatment of TA. Our results justify a randomized, controlled clinical trial of anti-TNF therapy for TA.