Arthritis following dyzentery or urethritis was mentioned before our era and later by many others. In 1818 Benjamin Brodie described 5 patients with typical „ Reiters disease”: urethritis, conjunctivitis, arthritis. Many diagnostic criteria for Reiters disease / reactive arthritis have been proposed for practical purpose the most acceeptable is the folowing one: posturethritic or postenterocolitic arthritis is Reiters disease / reactive arthritis. The findings of Chlamydiy from the synovia or in the synovial fluid of itients with RD suggest that arthritis may be of infective but not of reactive origin.