The foot and ankle are common sites of involvement in adult-onset rheumatoid arthritis and its seronegative variants, which include psoriatic arthritis, reactive arthritis, and ankylosing spondylitis. Multiple findings on physical examination are typical of these diseases, including pain, swelling, deformity, and stiffness of joints in the forefoot, midfoot, and hindfoot. Characteristic findings on imaging studies include subchondral erosion of bone into the articular surface, joint destruction, and joint-space narrowing. Nonsurgical treatment for immunologic rheumatic disorders of the foot and ankle usually includes a combination of pharmacologic therapy and the appropriate use of orthoses, bracing, or other modalities. Surgical treatment may be necessary, and is directed to the joints, tendons, and ligaments that are involved.