Methods of treating, inhibiting, or ameliorating arthritis, including rheumatoid arthritis, osteoarthritis, psoriatic arthritis, ankylosing spondylitis, or juvenile rheumatoid arthritis, in a human subject in need thereof, comprising administering to a subject in need a therapeutic amount of an interleukin 1 (IL-1) antagonist, wherein arthritis inhibited, or ameliorated. The IL-1 antagonist is an IL-1-specific fusion protein comprising an IL-1 binding portion of the extracellular domain of human II-1RAcP, an IL-1 binding portion of the extracellular domain of human IL-1RI, and a multimerizing component antagonist, preferably comprising a sequence selected from the group consisting of SEQ ID NO:4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, or a substantially identical sequence.