The purpose of this study is to assess the safety and efficacy of daclizumab as an adjunctive treatment to methotrexate in maintaining remission that has been induced by cyclophosphamide and glucocorticoids in patients with Wegener's granulomatosis. In this study, all patients will initially receive daily cyclophosphamide and glucocorticoids and then at disease remission, cyclophosphamide will be discontinued and patients will receive methotrexate for remission maintenance. Following the switch to methotrexate and when the prednisone dose has been tapered to 20mg QOD (plus or minus 10mg QOD), patients in remission will be randomized to receive daclizumab or not receive daclizumab. Those randomized to receive daclizumab will be treated with 1 mg/kg intravenously on day 0, week 2, week 4 and every month thereafter for a total of 18 months (20 doses). Regardless to which arm the patient is randomized, they will continue to receive methotrexate. Two years after the methotrexate was started, if the patient remains in remission, this will be tapered and discontinued. Patients will be prospectively monitored for evidence of disease relapse and drug toxicity. Specific parameters that will be obtained include the time to disease remission, the rate and time of disease relapse, and the incidence of drug-related adverse events.