This study will determine if the drug etanercept, also called Enbrel, is effective in producing and maintaining remission (reduction of disease symptoms) of Wegener's granulomatosis (WG). Etanercept blocks the action of tumor necrosis factor-alpha, a substance that may be involved in inflammatory conditions such as WG. Eight clinical centers around the United States will enroll 181 people who have WG. Patients will have an equal chance to receive either etanercept or placebo (inactive treatment). We will treat patients with standard medications for WG in addition to either etanercept or placebo. We will treat all patients with tapering doses of corticosteroids.