The diagnosis of rheumatoid arthritis is mainly based on the clinical findings showing in typical cases a bilateral symmetrical polysynovitis predominantly on the small hand and feet joints, without any other extra-rheumatological feature. Even this clinical presentation is very suggestive of the diagnosis, other diagnoses of diseases life and or function threatening (septic arthritis, viral arthritis, arthritis related to hemopathy, systemic vasculitis ...) have to be systematically evocated. The interest of an early diagnosis of rheumatoid arthritis is to facilitate the treatment and the monitoring of the patients since such treatment seems to be more efficient when initiated at an early stage of the disease.