The term reactive arthritis (RA) refers to an inflammatory joint disease in the absence of bacteria in the joint, but which is caused by a distant extra-articular infection. They occur as a result of a variety of infections, which are essentially genital or gastro-intestinal in subjects with a particular genetic predisposition characterized by the presence of the HLA-B27 antigen or one of the CREG group of antigens (B7 - B27 - BW22 - BW42). The most complete clinical expression of reactive arthritis is the Fiessinger-Leroy-Reiter syndrome. Apart from the reactive arthritis with a generally accepted aetiology such as those following infections of the genital tract (Chlamydia trachomatis, Ureaplasma urealyticum or of the gastrointestinal tract: Yersinia enterocolitica and pseudotuberculosis, Shigella flexneri, Salmonella minor, Campylobacter jejuni), the authors discuss the possibility of including, in a broader definition of RA, post-streptococcal arthritis and cases of arthritis following gonococcal, meningococcal and Brucella infections. RA does not always have a favourable clinical course. It is not exceptional to see a picture of recurrences with progression towards chronic inflammatory rheumatism.