Articular involvement following Borrelia burgdorferi invasion into synovial tissue, is one of the typical clinical forms of Lyme borreliosis. It may manifest itself at any stage of the disease and has a wide clinical spectrum, from transient musculoskeletal symptoms to chronic, persistent inflammation of the large joints. Typically, however, the natural course of the disease is favorable, leading to elimination of the spirochete and regression of symptoms even if untreated. Antibiotic therapy is highly effective in eliminating Borrelia burgdorferi at any stage of the disease, but in minority of antibiotically treated patients autoimmunological phenomena may account for prolonged inflammation. Diagnosis is based on detection of specific antiborrelial antibodies in patients with history and symptoms consistent with Lyme arthritis. Results of the serologic examinations must be interpreted with caution, as their specificity in recognizing active infection is limited.