Nine cases of peripheral arthritis were identified among 40 patients with brucellosis, in the endemic area of Southwestern Greece, during a 4-year prospective study. In 5 patients the joint was aspirated and the examination of the synovial fluid revealed white cell counts ranging from 4,460/mm3 to 8,800/mm3, with lymphocytic predominance. Synovial fluid cultures were positive for Brucella in 3 out of the 5 patients. These findings suggest that brucella arthritis is mainly a true septic arthritis, with characteristic joint fluid features, which distinguish it from other septic arthritides, a fact that is extremely helpful in its early diagnosis and management in an endemic area.