A positive rheumatoid factor (RF) test has been included as one of the criteria for the diagnosis of rheumatoid arthritis (RA) according to the 1987 classification criteria of the American College of Rheumatology (ACR). During the past 20-30 years many different autoantibodies have been described in patients with RA. The presence of some of the autoantibodies in RA directed against various autoantigens, such as anti-neutrophil cytoplasmic antibodies, anti-nuclear antibodies, antibodies against interleukin-1 (IL-1), anti-cardiolipin antibodies, and antibodies against oxidized low density lipoprotein, is not specific for RA and these are not discussed here. This review summarizes the most relevant autoantibodies, and discusses their sensitivity, specificity, and possible diagnostic and prognostic significance in early RA. The antibodies are presented with the two clinically most relevant antibody tests first, followed by others in alphabetic order.