Superoxide dismutase functions as a scavenger of superoxide radical protecting living organisms. This enzyme has potential use as anti-inflammatory or anti-reperfusion injury drug. Here we present a simple and efficient SOD purification method from human placental blood. Superoxide dismutase from clarified haemolysed placental blood after chloroform and ethanol treatment was purified by DEAE-Sepharose, Phenyl-Sepharose chromatographies and cross flow ultrafiltration. The purified product is 98% pure by SDS-PAGE with 71% yield and specific activity of 2.8 x 10(5) U/mg protein.