BACKGROUND: Takayasu arteritis is a rare form of chronic inflammatory disease of the large arterial vessels. Some patients do not respond to steroids or immunosuppressant drugs. OBJECTIVE: To evaluate the effect of mycophenolate mofetil in patients with severe Takayasu arteritis. DESIGN: Case series. SETTING: Clinical Research Center for Rare Diseases in Bergamo, Italy. PATIENTS: Three patients with Takayasu arteritis. INTERVENTION: Mycophenolate mofetil (2 g/d) given orally in two divided doses. MEASUREMENTS: Clinical evaluation and assessment of leukocyte counts were done weekly. Vascular lesions were assessed by using Doppler ultrasonography. RESULTS: All patients showed clinical benefit, and two resumed work after months of inactivity. Patients were also able to taper and discontinue steroid use. Mycophenolate mofetil was well tolerated, and no signs of toxicity were observed. CONCLUSIONS: Mycophenolate mofetil may be an alternative to steroids and cytotoxic agents in patients with Takayasu arteritis. Before results of controlled trials become available, mycophenolate mofetil should be considered only for patients who do not improve or stabilize with conventional therapy.