Reactive arthritis (ReA) is an aseptic, immune mediated arthritis with typical manifestations following urogenital, gastrointestinal or respiratory tract infections. The interval between the antecedent infection and arthritis is ranging from several days to 4-6 weeks. ReA is classified as member of the group of spondyloarthritides. The triggering microorganisms are not culturable by routine methods from the affected joints. In the pathogenesis of ReA, bacterial and immunological as well as genetic factors (HLA-B27) play an important role. Post-streptococcal arthritis, Lyme arthritis (Borreliosis) and viral arthritis are not classified as ReA within the spondyloarthritis group. In the treatment of ReA, antibiotics are not used. Acute ReA is treated by nonsteroidal anti-inflammatory drugs, and refractory (chronic) arthritis by steroids, sulfasalazine and TNF inhibitors. Notably, only a few original papers on ReA have been published within the last years.