Extracellular phospholipase A2 found in inflamed sites of human and rat was purified and characterized. Phospholipase A2 isolated from peritoneal exudates of rat treated with casein, that isolated from human synovial fluids in rheumatoid arthritis, that secreted from activated platelets of rat and rabbit share common structural and biochemical features. Possible roles, dynamics and regulation of these extracellular phospholipases in inflammatory processes will be discussed.